If the actual condition of the property varies from the target condition agreed in the contract (e.g. leaking roof), this is referred to as a defect in the rented property. The tenant may request that the defect be rectified if the tenant is not responsible for the defect, and the matter is not a minor repair or improvement. Furthermore the tenant may assert a proportionate reduction in the rental tariff, compensation for damages (insofar as he has suffered damage) and further rights in respect of implementing the rectification of defects.
A further area, which time and again gives rise to disputes, involves the so-called incidental costs. These are costs that are incurred by the lessor but are associated with use of the rented property (e.g. heating costs, cost of the building maintenance and waste water costs etc.). The lessor may apportion these to the tenant. Usually, a system of down payments is chosen, i.e. the tenant pays a certain amount each month, and the lessor settles these annually. However, the lessor may only settle incidental costs which are capable of being applied as incidental costs, which actually apply and are specifically described in the tenancy agreement. There is also a system involving flat-rate payments in which compensation for the incidental costs is specified in advance, and as a general rule cannot be amended during the term of contract.
In the case of sub-letting, the tenant lets the rented property to a third party, the sub-tenant. Sub-tenancy is generally permitted in Switzerland, whereby in most cases approval by the lessor is required. However, the lessor may only refuse permission for certain reasons.