Judgment of the Court (Ninth Chamber) of 11 June 2026.#DJ et PJ v Santander Bank Polska S.A.#Request for a preliminary ruling from the Sąd Okręgowy w Warszawie.#Reference for a preliminary ruling – Consumer protection – Directive 93/13/EEC – Unfair terms in consumer contracts – Article 6(1) and Article 7(1) – Loan agreement denominated in a foreign currency and containing unfair terms – Effects of the finding that a contractual term is unfair – Void agreement – Actions for restitution – Consumer’s right to default interest at the statutory rate on amounts to be repaid by the seller or supplier – National case-law requiring the payment of default interest at the statutory rate from the date on which the demand for payment was served indicating the specific amount of the claim – Dissuasive effect of the prohibition on unfair terms – Principle of effectiveness.#Case C-903/24.

Provisional text

JUDGMENT OF THE COURT (Ninth Chamber)

11 June 2026 (*)

( Reference for a preliminary ruling – Consumer protection – Directive 93/13/EEC – Unfair terms in consumer contracts – Article 6(1) and Article 7(1) – Loan agreement denominated in a foreign currency and containing unfair terms – Effects of the finding that a contractual term is unfair – Void agreement – Actions for restitution – Consumer’s right to default interest at the statutory rate on amounts to be repaid by the seller or supplier – National case-law requiring the payment of default interest at the statutory rate from the date on which the demand for payment was served indicating the specific amount of the claim – Dissuasive effect of the prohibition on unfair terms – Principle of effectiveness )

In Case C‑903/24 [Zmarka], (i)

REQUEST for a preliminary ruling under Article 267 TFEU from the Sąd Okręgowy w Warszawie (Regional Court, Warsaw, Poland), made by decision of 23 December 2024, received at the Court on 23 December 2024, in the proceedings

DJ

PJ

v

Santander Bank Polska S.A.,

THE COURT (Ninth Chamber),

composed of N. Jääskinen, acting as President of the Chamber, R. Frendo (Rapporteur) and A. Kornezov, Judges,

Advocate General: R. Norkus,

Registrar: A. Calot Escobar,

having regard to the written procedure,

after considering the observations submitted on behalf of:

–        Santander Bank Polska S.A., by A. Karpińska and B. Kubiak, radcowie prawni,

–        the Polish Government, by B. Majczyna, acting as Agent,

–        the Portuguese Government, by A. Pimenta and A. Rodrigues, acting as Agents,

–        the European Commission, by P. Kienapfel and A. Szmytkowska, acting as Agents,

having decided, after hearing the Advocate General, to proceed to judgment without an Opinion,

gives the following

Judgment

1        This request for a preliminary ruling concerns the interpretation of Article 6(1) and Article 7(1) of Council Directive 93/13/EEC of 5 April 1993 on unfair terms in consumer contracts (OJ 1993 L 95, p. 29) and of the principle of effectiveness.

2        The request has been made in proceedings between DJ and PJ, two consumers, and Santander Bank Polska S.A. (‘SBP’), a bank established in Poland, concerning, inter alia, a claim for payment of default interest at the statutory rate on the sums paid to SBP under a loan agreement declared void on account of the unfair terms contained therein.

 Legal context

 European Union law

3        The twenty-fourth recital of Directive 93/13 states that ‘the courts or administrative authorities of the Member States must have at their disposal adequate and effective means of preventing the continued application of unfair terms in consumer contracts’.

4        Article 6(1) of that directive provides:

‘Member States shall lay down that unfair terms used in a contract concluded with a consumer by a seller or supplier shall, as provided for under their national law, not be binding on the consumer and that the contract shall continue to bind the parties upon those terms if it is capable of continuing in existence without the unfair terms.’

5        Article 7(1) of that directive provides:

‘Member States shall ensure that, in the interests of consumers and of competitors, adequate and effective means exist to prevent the continued use of unfair terms in contracts concluded with consumers by sellers or suppliers.’

 Polish law

 The Civil Code

6        Article 385¹(1) and (2) of the ustawa – Kodeks cywilny (Law establishing the Civil Code) of 23 April 1964 (Dz. U. of 1964, No 16, item 93), in its version applicable to the dispute in the main proceedings (‘the Civil Code’) provides:

‘1.      The terms of a contract concluded with a consumer which have not been individually negotiated shall not be binding on the consumer if his or her rights and obligations are set forth in a way that is contrary to the accepted principles of morality and manifestly infringes his or her interests. This provision shall not apply to terms setting out the principal obligations to be performed by the parties, including price or remuneration, so long as they are worded clearly.

2.      If a contractual term is not binding on the consumer pursuant to paragraph 1, the contract shall otherwise continue to be binding on the parties.’

7        Article 481 of that code provides:

‘1.      If a debtor is late in performing a financial obligation, the creditor may demand default interest, even if he or she has suffered no loss and even if the delay is due to circumstances for which the debtor is not responsible.

2.      If the default interest rate has not been specified, default interest shall be payable at the statutory rate …

…’

 Law establishing the Code of Civil Procedure

8        Article 203(4) of the ustawa Kodeks postępowania cywilnego (Law establishing the Code of Civil Procedure) of 17 November 1964 (Dz. U. of 1964, No 43, item 296), in the version applicable to the dispute in the main proceedings (‘the Code of Civil Procedure’), provides:

‘The court may declare the discontinuance, abandonment or limitation of a claim inadmissible only if the circumstances of the case show that such acts are contrary to the law or to the principles of social life or that they are intended to circumvent the law.’

 The dispute in the main proceedings and the question referred for a preliminary ruling

9        On 26 September 2008, DJ and PJ entered into a loan agreement with SBP concluded for a period of 348 months, denominated in Swiss francs, under which SBP granted them a loan of 50 000 zlotys (PLN) (approximately EUR 11 500) (‘the agreement at issue’). According to the terms of that agreement, the monthly repayments of that loan were to be paid in zlotys after their conversion by applying the selling rate for the Swiss franc in accordance with the table of exchange rates in force at the bank on the date of repayment (‘the conversion clauses’).

10      Between 3 October 2008 and 12 July 2022, DJ and PJ paid SBP an amount of PLN 54 290.71 (approximately EUR 12 500) in performance of the agreement at issue.

11      On 25 July 2022, SBP was served with a complaint by DJ and by PJ in which it was argued that the agreement at issue was void on account of the unfair terms contained therein. Consequently, DJ and PJ served SBP with a demand for payment to return to them, within 30 days, ‘an amount corresponding to the sum of all the principal and interest instalment repayments made under [that agreement]’.

12      On 18 November 2022, DJ and PJ brought an action before the Sąd Okręgowy w Warszawie (Regional Court, Warsaw, Poland), which is the referring court, seeking a declaration that the agreement at issue was void on the ground that the conversion clauses were unfair and an order that SBP repay them an amount of PLN 54 290.71 (approximately EUR 12 500), corresponding to the monthly instalments paid under that agreement, together with default interest at the statutory rate, from 17 August 2022 until the date of payment.

13      Before the referring court, SBP argued that the agreement at issue was valid in so far as it did not contain unfair terms and contended that the action should be dismissed.

14      On 25 July 2024, SBP raised before that court a plea of set-off of its claim of PLN 50 000 (approximately EUR 11 500), corresponding to the principal of the loan paid to DJ and PJ, against the claim relied on by them before that court, following which, on 6 November 2024, DJ and PJ withdrew their claim in respect of the amount of PLN 50 000 (approximately EUR 11 500), while maintaining the remainder of the claim.

15      On 14 November 2024, the referring court delivered a partial judgment in which it declared the agreement at issue void on the ground that the conversion clauses were unfair and that that agreement could not continue in existence without those clauses. By order of 29 November 2024, that court discontinued the proceedings for payment of the amount of PLN 50 000 (approximately EUR 11 500).

16      As to the remainder, that court considers that DJ’s and PJ’s claim for payment of PLN 4 290.71 (approximately EUR 1 000) is well founded. By contrast, as regards their claim that SBP should be ordered to pay default interest at the statutory rate, the referring court states that it has doubts as to the determination of the date from which that interest must begin to run.

17      That court is uncertain whether that interest must be granted from the date on which SBP was notified of the pre-litigation demand for payment, namely the complaint, or only from the date of service on the bank of the application initiating proceedings. That question stems from the fact that, in the complaint, DJ and PJ did not indicate the specific amount of the claim relied on against SBP, while that amount was indicated precisely in that application. Thus, that court asks whether it must be held that default interest runs only from the date of a request for payment of the claim, sent by the consumer to the seller or supplier, containing a specific indication of the amount of that claim.

18      The referring court notes that although the provisions of the Civil Code do not contain any formal requirement as to the content of the demand for payment, national case-law and legal literature indicate that, in order to trigger the obligation to pay default interest, it must include a request for payment of a specific amount.

19      That court is uncertain whether such a requirement constitutes an unreasonable obstacle for the consumer which would prevent him or her from enforcing the default interest allegedly due, in breach of Article 6(1) and Article 7(1) of Directive 93/13, and of the principle of effectiveness. If the consumer fails to indicate the specific amount in the demand for payment, the seller or supplier from whom payment is sought will not be obliged to pay default interest at the statutory rate.

20      It is apparent from the case-law of the Court that the obligation on the national court to remove an unfair contractual term entails, in principle, the restitution of sums unduly paid. The absence of a full restitutory effect would be liable to call into question the dissuasive effect that Article 6(1) of Directive 93/13, read in conjunction with Article 7(1) of that directive, is designed to attach to a finding of unfairness in respect of terms in contracts concluded between consumers and sellers or suppliers. Therefore, a limitation of the consumer’s rights regarding the award of default interest at the statutory rate would weaken the restitutory effect and, consequently, the dissuasive effect, since it would, in essence, allow the seller or supplier to disregard the demand for payment sent by the consumer, if the specific amount claimed by the consumer is not indicated therein.

21      Thus, according to the referring court, it could be considered, on the one hand, that the consumer should not be subject to the obligation to indicate to the seller or supplier the specific amount claimed in order to cause default interest to accrue. In particular, in so far as a bank is a specialised institution which uses financial documents and computer systems for the purposes of its activities, it is at any time in a position to determine rapidly and easily the amount of loan instalments paid by the consumer over the entire term of the loan or part thereof.

22      On the other hand, the obligation on the consumer to quantify precisely his or her claim in order for default interest owed by the seller or supplier to accrue could be regarded as reasonable and justified. In so far as the consumer pays the loan instalments, he or she is aware of the amounts paid to the bank and can check them in the history of his or her bank account or ask the bank to issue the corresponding certificate. In the present case, DJ and PJ obtained, one week after the complaint was lodged, a certificate from the bank indicating the amount of all the instalments of the loan repaid until then, with the result that they could have renewed the complaint by supplementing it with an indication of the specific amount of their claim. In addition, DJ and PJ are represented by a lawyer subject to a duty of care, breach of which could give rise to compensation in favour of his clients.

23      In those circumstances, the Sąd Okręgowy w Warszawie (Regional Court, Warsaw) decided to stay the proceedings and to refer the following question to the Court of Justice for a preliminary ruling:

‘Must Article 6(1) and Article 7(1) of [Directive 93/13] and the principle of effectiveness be interpreted as precluding a judicial interpretation of national legislation under which a court may order a seller or supplier to pay statutory default interest to a consumer on the amount of an undue payment made on the basis of an unfair contractual term only from the date on which the seller or supplier is served with a demand for payment indicating the specific amount sought by the consumer[?]’

 On the need to adjudicate

24      According to settled case-law, the procedure provided for in Article 267 TFEU is an instrument of cooperation between the Court and the national courts by means of which the Court provides the national courts with the points of interpretation of EU law which they need in order to decide the disputes before them (see order of 26 January 1990, Falciola, C‑286/88, EU:C:1990:33, paragraph 7, and judgment of 29 July 2024, LivaNova, C‑713/22, EU:C:2024:642, paragraph 52 and the case-law cited).

25      In that regard, it should be borne in mind, however, that the justification for a reference for a preliminary ruling is not that it enables advisory opinions on general or hypothetical questions to be delivered but rather that it is necessary for the effective resolution of a dispute. Therefore, if it appears that the question raised is manifestly no longer relevant for the purposes of deciding the case, the Court must declare that there is no need to proceed to judgment (judgment of 24 November 2022, Banco Cetelem, C‑302/21, EU:C:2022:919, paragraph 31 and the case-law cited).

26      Since it is apparent from both the wording and the scheme of Article 267 TFEU that the preliminary ruling procedure presupposes that a dispute is actually pending before the national courts in which they are called upon to give a decision which is capable of taking account of the preliminary ruling, the Court must find that there is no need to adjudicate if the dispute in the main proceedings has become devoid of purpose (judgment of 24 November 2022, Banco Cetelem, C‑302/21, EU:C:2022:919, paragraph 32 and the case-law cited).

27      In the present case, on 4 November 2025, the referring court sent to the Court its order of 13 October 2025 by which it held that the partial withdrawal of the applicants in the main proceedings of 10 April 2025, resulting from the withdrawal of their request for payment of default interest for the period from 25 July 2022 to 9 February 2023, was inadmissible, pursuant to Article 203(4) of the Law establishing the Code of Civil Procedure, in its version applicable to the dispute in the main proceedings. In particular, having noted that the parties had not reached an amicable settlement and that the claim of the applicants in the main proceedings had not been satisfied in any way, the referring court concluded that the purpose of the partial withdrawal was to achieve the withdrawal of the request for a preliminary ruling, that withdrawal having to be classified as contrary to life in society and as seeking to circumvent the law.

28      Following the request for clarification sent to it, pursuant to Article 101 of the Rules of Procedure of the Court of Justice, on 12 November 2025, the referring court, by its reply received at the Court Registry on 4 December 2025, stated that the order of 13 October 2025 was not open to appeal and therefore had the force of res judicata. In addition, the referring court confirmed that, depending on the Court’s answer, the applicants in the main proceedings could be granted default interest on the amount of their claim for the period from 25 July 2022 to 9 February 2023, despite their intention no longer to collect it for that period. Consequently, in the context of the present case, the referring court considers that it is required to examine the substance of the borrowers’ claim seeking from the bank payment of default interest at the statutory rate for that period, the decision being, in that regard, dependent on the answer which the Court will give to the question referred for a preliminary ruling.

29      Thus, it is apparent from the file before the Court that an answer to the question referred for a preliminary ruling appears necessary for the resolution of the dispute before the referring court.

30      In those circumstances, there is a need to adjudicate on the present request for a preliminary ruling.

 The jurisdiction of the Court

31      SBP and the Portuguese Government submit that the Court does not have jurisdiction to hear and determine the request for a preliminary ruling, since, by that request, the referring court is, in essence, asking the Court to interpret national law.

32      SBP claims that the issues raised by the question referred do not require an interpretation of Directive 93/13, which does not govern the consequences of an agreement being void. SBP adds that the request for a preliminary ruling cannot concern a matter regulated by the Polish legislature. Thus, first, given that that legislature has already regulated matters relating to the demand for payment mechanism and, consequently, the enforceability of the claim, the delivery of a decision on the substance by the Court constitutes an excessive interference with the Polish legal order. Second, a distinction between the legal situation of borrowers who are consumers and that of any other borrower would lead, in particular, to an infringement of Articles 20 and 47 of the Charter of Fundamental Rights of the European Union (‘the Charter’).

33      In that regard, it should be borne in mind that, in proceedings under Article 267 TFEU, which are based on a clear separation of functions between the national courts and the Court, the national court alone has jurisdiction to interpret and apply national law, while the Court is empowered only to give rulings on the interpretation or the validity of an EU provision on the basis of the facts which the national court puts before it (see judgments of 16 March 1978, Oehlschläger, 104/77, EU:C:1978:69, paragraph 4, and of 18 December 2025, Jouxy and Others, C‑296/24 to C‑307/24, EU:C:2025:999, paragraph 22 and the case-law cited).

34      In the present case, the question referred expressly concerns the interpretation of Article 6(1) and Article 7(1) of Directive 93/13, read in the light of the principle of effectiveness. The referring court asks, in essence, whether those provisions and that principle are compatible with the judicial interpretation of national legislation concerning the award of default interest according to which, where a loan agreement concluded with a consumer by a seller or supplier has been annulled on account of unfair terms contained therein, that seller or supplier may be ordered to pay the consumer default interest at the statutory rate on the amount of the consumer’s claim only from the time when the document notified to him or her by the consumer indicates the specific amount for which repayment is sought.

35      Contrary to what SBP and the Portuguese Government argue, the referring court thus seeks an interpretation of an EU act.

36      Accordingly, it is for the Court to provide the referring court with all the guidance as to the interpretation of EU law which will enable it to rule itself on the compatibility of its national law, as interpreted by national case-law, with EU law.

37      Consequently, since the Court has jurisdiction to interpret the provisions and principles of EU law, it has jurisdiction to rule on the request for a preliminary ruling and to answer the question referred to it by the referring court.

 Consideration of the question referred

38      By its question, the referring court asks, in essence, whether Article 6(1) and Article 7(1) of Directive 93/13, read in the light of the principle of effectiveness, preclude a judicial interpretation of national law according to which, following the annulment of a loan agreement concluded between a consumer and a seller or supplier, on the ground that that agreement cannot continue in existence after the removal of the unfair terms contained therein, that seller or supplier may be ordered to pay that consumer default interest at the statutory rate on the amount of the consumer’s claim only from the date on which that consumer notifies that seller or supplier of an extrajudicial document or a procedural document indicating the specific amount sought by the consumer.

39      Under Article 6(1) of Directive 93/13, Member States are to lay down that unfair terms used in a contract concluded with a consumer by a seller or supplier are, as provided for under their national law, not to be binding on the consumer.

40      In addition, given the nature and significance of the public interest constituted by the protection of consumers, who are in a position of weakness vis-à-vis sellers or suppliers, Directive 93/13, as is apparent from Article 7(1) thereof, read in conjunction with its twenty-fourth recital, obliges the Member States to provide for adequate and effective means ‘to prevent the continued use of unfair terms in contracts concluded with consumers by sellers or suppliers’ (judgment of 22 January 2026, Herchoski, C‑902/24, EU:C:2026:42, paragraph 56 and the case-law cited).

41      Therefore, the national court is obliged to exclude an unfair contract term imposing the payment of amounts that prove not to be due. Such an obligation entails, in principle, a corresponding restitutory effect in respect of those same amounts, in so far as the absence of such a restitutory effect would call into question the dissuasive effect which Article 6(1) of that directive, read in conjunction with Article 7(1) thereof, is designed to attach to a finding of unfairness in respect of terms in contracts concluded between consumers and sellers or suppliers (judgment of 22 January 2026, Herchoski, C‑902/24, EU:C:2026:42, paragraph 57 and the case-law cited).

42      It should be noted, in that regard, that Directive 93/13 does not expressly govern the consequences of the invalidity of a contract concluded between a seller or supplier and a consumer after the excision of the unfair terms in that contract. Accordingly, it is for the Member States to determine the consequences of such invalidity, it being understood that the rules which they lay down in that regard must be compatible with EU law and, in particular, with the objectives pursued by that directive (judgment of 22 January 2026, Herchoski, C‑902/24, EU:C:2026:42, paragraph 58 and the case-law cited).

43      In the absence of specific EU legislation on the subject, the detailed rules for implementing the consumer protection provided for by Directive 93/13 are a matter for the domestic legal order of the Member States by virtue of the principle of their procedural autonomy. However, those rules must not be less favourable than those governing similar domestic actions (principle of equivalence), nor may they be framed in such a way as to make it in practice impossible or excessively difficult to exercise the rights conferred by EU law (principle of effectiveness) (judgment of 14 December 2023, Getin Noble Bank (Limitation period for actions for restitution), C‑28/22, EU:C:2023:992, paragraph 60 and the case-law cited).

44      As regards the principle of effectiveness, which alone is the subject of the issues raised by the referring court, it should be borne in mind that every case in which the question arises as to whether a national provision makes the application of EU law impossible or excessively difficult must be analysed by reference to the role of that provision in the procedure, its progress and its special features, viewed as a whole, before the various national bodies. In that context, it is necessary to take into consideration, where relevant, the principles which lie at the basis of the national legal system, such as the protection of the rights of the defence, the principle of legal certainty and the proper conduct of the proceedings (judgment of 22 January 2026, Herchoski, C‑902/24, EU:C:2026:42, paragraph 77 and the case-law cited).

45      In addition, the Court has stated that the obligation on the Member States to ensure the effectiveness of the rights that individuals derive from EU law, particularly the rights deriving from Directive 93/13, implies a requirement for effective judicial protection, also guaranteed in Article 47 of the Charter, which applies, inter alia, to the definition of detailed procedural rules relating to actions based on such rights (judgment of 18 December 2025, Soledil, C‑320/24, EU:C:2025:993, paragraph 29 and the case-law cited).

46      In the present case, it is apparent from the order for reference that the Civil Code does not lay down any requirement as to the obligation to quantify the amount of which repayment is sought by a creditor in the context of a demand for payment. Nevertheless, according to national case-law, in order to produce effects such as the right of the latter to receive default interest, that demand for payment must include a request for payment of a specific amount.

47      Thus, a seller or supplier can be ordered to pay a consumer default interest at the statutory rate on the amount unduly paid by that consumer on the basis of an unfair contractual term only from the date of service on that seller or supplier of an extrajudicial document or a procedural document indicating the specific amount sought by that consumer.

48      In that regard, it should be noted that, first, the requirement that a consumer indicate, in an extrajudicial or procedural document, the specific amount of which he or she seeks repayment enables the seller or supplier, as the debtor, to acquaint himself or herself with the amount of the obligation to be enforced and to assess whether it is well founded.

49      Second, the indication of the specific amount of the claim at the demand for payment stage does not place an excessive burden on the consumer who knows the amounts paid to the seller or supplier, in this case to the bank, and may, where appropriate, verify them in the history of his or her bank account or ask the bank to issue to him or her a certificate showing the amount of all the loan instalments already repaid.

50      Consequently, in the light of the case-law referred to in paragraph 43 of the present judgment, such a requirement cannot be regarded as making it in practice impossible or excessively difficult to exercise the rights conferred on consumers by Directive 93/13.

51      Furthermore, the fact that, in the present case, the consumers are represented by a lawyer does not affect the preceding analysis. The general question concerning the obligation to indicate such an amount in order to be able to claim default interest must be settled independently of the specific circumstances of each case (see, to that effect, judgment of 11 March 2020, Lintner, C‑511/17, EU:C:2020:188, paragraph 40).

52      In the light of the foregoing considerations, the answer to the question referred is that Article 6(1) and Article 7(1) of Directive 93/13, read in the light of the principle of effectiveness, must be interpreted as not precluding a judicial interpretation of national law according to which, following the annulment of a loan agreement concluded between a consumer and a seller or supplier, on the ground that that agreement cannot continue in existence after the removal of the unfair terms contained therein, that seller or supplier may be ordered to pay that consumer default interest at the statutory rate on the amount unduly paid by that consumer in the performance of that agreement only from the date on which that consumer notifies that seller or supplier of an extrajudicial document or a procedural document indicating the specific amount sought by the consumer.

 Costs

53      Since these proceedings are, for the parties to the main proceedings, a step in the action pending before the referring court, the decision on costs is a matter for that court. Costs incurred in submitting observations to the Court, other than the costs of those parties, are not recoverable.

On those grounds, the Court (Ninth Chamber) hereby rules:

Article 6(1) and Article 7(1) of Council Directive 93/13/EEC of 5 April 1993 on unfair terms in consumer contracts, read in the light of the principle of effectiveness,

must be interpreted as not precluding a judicial interpretation of national law according to which, following the annulment of a loan agreement concluded between a consumer and a seller or supplier, on the ground that that agreement cannot continue in existence after the removal of the unfair terms contained therein, that seller or supplier may be ordered to pay that consumer default interest at the statutory rate on the amount unduly paid by that consumer in the performance of that agreement only from the date on which that consumer notifies that seller or supplier of an extrajudicial document or a procedural document indicating the specific amount sought by the consumer.

[Signatures]

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*      Language of the case: Polish.

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i      The name of the present case is a fictitious name. It does not correspond to the real name of any party to the proceedings.