OSM and German local governments - question from a French geomatician

Hallo, I'm a French consultant in spatial information, and I don't speak german, sorry.

So, I will go on in english, sorry, and I hope that you will forgive me!

As Germany is quite more advanced on OSM than France, I would like to know if OSM is professionnaly used by the German local governments (Cities, Landers...). And if it is the case, who could I join in order to have an exchange with him about this experience (or experiment?).

I thank you everybody for your attention.
Serge Mang