Banking
There are some international banks operating in Germany and many German. In respect of international standards German banking business is still special.
Just a few banks meet the requirements of a good and advanced service. But many bankers do speak English. At least on POI.
Berlin House & Service Ltd. assits you to find the bank for you.
Mortgages
Mortgaging is costly in Germany due to attorney and notary fees !

The network of the German "Volksbanken"
Berliner Volksbank is a player in Berlin.