Before moving into an apartment you usually sign a lease with your future landlord. By signing it you enter into a legally binding agreement and should therefore read it carefully before signing, including the fine print. Purely verbal rental agreements are rather uncommon in Germany.
The lease should include the following information: basic monthly rental charge not including monthly additional costs such as garbage removal, water, taxes and, in some cases, heating and hot water (Kaltmiete), monthly additional costs (Nebenkosten), starting date and duration of the rental period (in the case of fixed-term leases), term of notice for open-ended contracts (usually 3 months), the tenant's rights of use (basement, common areas, garden etc.), possible obligatory make good/repairs before moving out (professional carpet cleaning, painting etc). Any existing deficiencies in the flat should also be noted so that you will not be held responsible when moving out. Under German legislation, it is permissible to keep small pets (guinea pigs, caged birds, rabbits and hamsters). If you wish to keep cats or dogs, you should discuss this with your landlord in advance.
Some landlords will agree to terminate the tenancy before expiry of the notice period if you are able to provide a new tenant in time. If anything in your lease strikes you as strange or unusual, do not hesitate to consult the Goethe Welcome Centre.
It is common in Germany for a landlord to ask for 1 or 2 months’ rent as a security deposit. The money is put in a savings account for you and is paid back in full when you move out unless you have damaged the apartment or have not fully paid your rent. The maximum permissible deposit is three months rent. Before moving into your new appartment/house you should insist on a hand-over report to be well prepared for possible damage claims from the landlord when moving out again.
Also before moving in you usually make an appointment with your landlord to receive the keys.