By signing a tenancy agreement, you gain some rights, but also have special responsibilities. For example:
The monthly payment is due at the beginning of each month and consists of two parts, the rent (Kaltmiete) and the utilities (Nebenkosten). Whereas the Kaltmiete is generally fixed for the duration of the lease, utilities can vary from year to year. Nebenkosten usually include: water, heating, garbage collection, the landlord’s share in property tax, insurance for the land property, chimney cleaning, etc. Be aware that there are additional payments for electricity, water, heat, etc. depending on the amount used.
As a security for any damage or unpaid rent, the landlord will ask for a refundable security deposit (Kaution) amounting to two or three months’ rent. After the lease ends and the property has been handed back without damages according to the protocol signed together with the lease, the deposit plus the legal interest rate for the period of the lease must be paid back.
It is common in Germany to have unfurnished flats, which also means that, especially in larger flats, you might have no kitchen equipment like a stove or a sink. If there is furniture, this will be described in the advertisement as (teil-)möbliert, i.e. (partly) furnished.
If a phone number is indicated, you can call the landlord or real estate agent directly. In case of language difficulties ask a friend or colleague to help you arrange a viewing appointment.
Make sure that you have completely understood the tenancy agreement before you sign it. Ask a German colleague or friend to read the contract.