Introduction of the system of effective costs for the collection of ancillary costs previously included in the rent

Facts

The dispute opposes the tenants of a rental property owned by the cooperative society C. to the latter. The rental contracts set a minimum net rent and an amount of deposit for heating and hot water. The cooperative society C. informed the tenants of the introduction of the system of effective costs for the collection of certain ancillary costs previously included in the rent, with payment of deposits. The tenants contested this modification before the Rent Conciliation Commission, then before the Vaud Cantonal Court of Rent, which ruled that the new claims were not abusive. The Vaud Cantonal Court's Court of Appeal dismissed the tenants' appeal for revision.

The tenants filed an appeal for revision with the Federal Court, concluding that the new claims of the cooperative society C. should be rejected. The Federal Court admitted the appeal.

Considerations

The Federal Court examined whether the cooperative society C. could unilaterally modify the rental contract to introduce the system of effective costs for the collection of ancillary costs previously included in the rent. It considered that art. 269d al. 3 CO authorizes the landlord to make unilateral changes to the contract, including the introduction of new ancillary costs, without requiring the occurrence of new circumstances.

The Federal Court also examined whether the cooperative society C. had respected the formal requirements for notifying unilateral changes to the contract. It considered that the official form had to contain the designation of the claims, the date of their entry into force, and the precise reasons justifying these claims. It ruled…