
Frequency
The landlord may raise the rent again at the earliest 12 months after the start of the tenancy or after the last rent increase.
Amount
How high the mark-up may be depends on the amount of the initial rent and the so-called local comparative rent. This is the rent that is usually paid for an apartment of a comparable type, size, furnishings, quality and location in the municipality.
Formalities
The rent increase must always be declared in text form. The landlord must also justify the increase in text form, for example by enclosing an expert opinion or naming three forms of comparison. Incidentally, if there are several tenants in the building, the increase must be requested by all of them, otherwise it is invalid.
Check
The Tenants' Association advises checking every increase. Tenants have the rest of the month in which they receive the letter and the following two months to do so. Tenants should also measure their living space: This is not stated correctly in all rental agreements, but a rent increase is only valid on the basis of the exact number of square meters.