Question juridique clé
Whether the unauthorized subletting justified anticipatory termination under Art. 257f para. 3 CO
Solution extraite
Yes. The landlord validly warned the tenant in writing, the tenant did not react, and the subletting amounted in substance to an abusive substitution of tenant.
Motifs extraits
A tenant who no longer intends to return and uses subletting to replace herself with a family member acts contrary to good faith. In such a case the landlord could have objected under Art. 262 CO, so the requirements of Art. 257f para. 3 CO were met.