I've been checking the rules here: apparently it is okay to camp if you have permission from the owner, and there are some places in the Black Forest where you can wild camp. Otherwise it is technically illegal to use an "enclosed shelter" i.e. a tent to sleep overnight, but a tarp is open, so it theoretically isn't illegal. Gotta love German exactitude...
Has anyone here wild camped in Germany?
I have too, and in Switzerland