Try Schönhagen, which is S of Berlin.
Home - Flugplatz Schönhagen
There is a flight school where you may find help. I haven't been there by myself, but as you said you can't find any websites this is at least a beginning.
Flugzeugcharter in Schönhagen bei Berlin
Note that Flugzeugcharter actually means aircraft rental.
Others at EDAZ:
http://www.aviation-project-service.com/en
HFD Flugschule und Rundflug - Service in Berlin/Brandenburg - Luftfahrzeuge