Facts
The dispute concerns the validity of a rent increase notified by the landlord T. to his tenant W. for July 1, 1995, i.e., after the tacit renewal of the lease with indexed rents.
The initial lease, concluded for 10 years from July 1, 1984 to June 30, 1994, provided for an indexation clause allowing the landlord to adapt the rent according to the variation of the Swiss consumer price index. After the expiration of this initial period, the lease was tacitly renewed from year to year.
The landlord notified a rent increase from CHF 2,030 to CHF 3,275 per month, motivated by the desire to obtain a return on equity of 6%. The tenant contested this increase, considering it to be abusive.
The cantonal courts rejected the landlord's claim, considering that the relative method should apply and that the increase was not justified, as the increase in cost of living had been offset by the decrease in the mortgage rate.
The landlord appealed to the Federal Tribunal, which upheld the appeal and remanded the case to the cantonal court for a new judgment.
Considerations
The Federal Tribunal considers that the jurisprudential principles developed in ATF 121 III 397 concerning leases with stepped rents also apply, mutatis mutandis, to leases with indexed rents.
Indeed, although the aleatory nature of the lease with indexed rents does not lie in the forecasts on the evolution of the factors of increase and decrease, it nevertheless exists due to the prohibition for the landlord to pass on other factors than the increase in cost…