Question juridique clé
Whether the tenant could invoke a violation of the social inquisitorial principle in taking evidence under Art. 274d(3) CO.
Solution extraite
No violation was shown; the cantonal court could refuse further evidence because the disputed facts were either irrelevant, already established, or unsupported by the file.
Motifs extraits
Art. 274d(3) CO does not oblige the court to hear witnesses for facts that can be proved by documents or that are not decisive. The tenant failed to show arbitrariness in the appreciation of evidence.