Contestation of the initial rent
According to the Federal Supreme Court, initial rents that are significantly higher than the previous rent are presumed to be abusive. Abusive initial rents must be reduced by the court in contestation proceedings. The landlord can prevent this reduction by rebutting the presumption of unfairness. To do so, he must prove that the rent demanded is customary and reasonable in the region. The landlord may also use comparable properties from the entire neighbourhood or even outside the neighbourhood.
If the landlord succeeds in raising sufficient doubts about the unfairness of the rent, the tenant must prove that the rent is actually excessive – which is often difficult in practice. This shift in the burden of proof to the tenant makes the judgement particularly significant. (Source: BGE 4A_121/2023 from 29.11.2023)