I don't have a direct line for you, but my experience as a lawyer in Australia means that I think you should be able to approach legal aid centres to ask if they have any recommendations for you. In addition to working as a corporate lawyer, I volunteered in legal advice centres after-hours, and we were always willing to assist people find the right legal help if we weren't able to provide it ourselves. The lawyers should be the same here...(although they may not be volunteers here...Germany is much wealthier). Either way, 1 minute of their time shouldn't hurt anyone.
If you come up with nothing else, it might be worth trying as a short cut:
Also of course, you can try to contact a German government representative through here, as source of information:
hope this helps and yes, good luck.
...would be good if you could share what you learn eventually...