I'd suspect the slave or master cylinder or perhaps the spring/mechanism/throwout (release) bearing.
In any event, this is a mechanical failure and shops accustomed to manual transmission/clutch issues should be able to help you, even if they are not "german auto" specializing shops.

If it were me, I'd take it to a local german auto repair facility, just the same. That is, unless you are brave enough to get into it yourself. It's a physical problem, not one of our car's horribly complex electrical gremlins, so I'd think a real "mechanic" can handle this. IT's what they do.