Notice of termination by the tenant
There are fixed-term and indefinite rental agreements. Without any written agreement between the parties that specifically states otherwise, it is assumed they have an indefinite rental agreement which can be terminated with notice.
Standard notice of termination
Either the tenant or the landlord can issue a notice of termination. In this, either the legal minimum term of notice or that established in the rental contract must be observed. If the parties have not reached any other specific agreement with regard to the date of notice of termination, it must be given according to those standard in the community.
An early notice of termination must also be issued in writing. It is effective on the next possible date of giving notice. The tenant can, however, move out without adhering to the notice period and date if he offers the landlord at least one (even better: several!) financially solvent and acceptable replacement tenant who would be willing to take over the apartment on the desired date and at the existing contractual rental terms and conditions.
The tenant is only freed of obligations after the new potential tenant has signed the rental contract. It is best to have this confirmed in writing by the landlord.
Type and date of the notice of termination
A notice of termination is to be made in writing and signed personally by all parties who signed the rental contract. The notice of termination must arrive to the hands of the landlord at the latest on the last day before the start of the notice period (when dealing with businesses, during business hours).
To provide evidence, it is strongly recommended to send the notice of termination by registered letter. This is considered to have reached the addressee on the day it is delivered or when it could have first been picked up at the post office.
If multiple tenants rent an apartment together (e.g. cohabitating couples, flat-sharing communities), each individual tenant can move out at any time, but that person continues to be collectively liable for the obligations arising from the jointly signed rental contract.
Renting and giving notice of termination jointly
When multiple tenants rent an apartment together, they can only give notice of termination jointly. The notice of termination of a single tenant is null and void and has no legal effect whatsoever.