In principle, landlords are not allowed to keep duplicate keys for rented apartments, even if tenants are on vacation for a longer period or are absent for other reasons. When handing over the apartment, the landlord must give the tenant all keys to the apartment (including cellar, letterbox and garage keys). If the landlord keeps a key without consulting the tenant beforehand, he is in breach of his cardinal obligation (Section 535, Paragraph 1 BGB), according to which the rented property must be "left" to the tenant. This transfer can only be fulfilled by the landlord by handing over all keys.
In addition, the landlord may only enter the rental property with the consent of the tenant after prior appointment. Usually this is the case when repairing or removing defects in the apartment. Even if the tenant voluntarily gives the landlord an apartment key, this does not constitute a right to enter the apartment without permission. Even if the rental agreement has already been signed and the tenant has not yet moved into the apartment, the landlord may not withhold any apartment key from the tenant.
The only exception that allows the landlord to enter the apartment without consulting the tenant is an emergency: if, for example, a water or gas pipe breaks, the landlord has the right to enter the apartment to prevent major damage. Therefore, the landlord can know where a spare key can be found. In an emergency, landlords may ask for the key’s location in order to avoid the costs of a locksmith.
In rental contracts, landlords often use formal clauses to justify the right to retain a duplicate key, but this is usually ineffective. Tenants and landlords can, however, make separate agreements, all of which, however, must be recorded - ideally in writing. It makes sense that the landlord and tenant create a way that enables the landlord to gain access to the rental property in an emergency. If the tenant does not want to provide the landlord with an emergency key, there are other options such as:
• Duplicate keys, which are deposited with a confidant of the tenant who also knows the landlord, or
• the landlord keeps the duplicate key in a closed envelope.
The tenant can tell whether the envelope has been opened or not if both parties sign over the flap or the envelope is sealed when it is handed over. Of course, the landlord must return such an apartment key at the request of the tenant.
But what if the landlord has a duplicate key without the tenant's knowledge or refuses to hand it over? In such a case, the tenant can, for example, change the door lock during the tenancy. If the tenant finds that the landlord - without an emergency would exist - enters the apartment with a duplicate key, the tenant can report the landlord to trespassing and terminate the lease without notice. Even if the tenant moves out of the apartment before the actual end of the contract and the landlord already has the apartment key, he is not allowed to enter the apartment with it. As long as the lease is running, the landlord needs the tenant's approval. He cannot be obliged by a clause in the rental agreement to hand over the apartment keys to the landlord before the end of the contract.