Longshot, but anyone know anything about German PhD system?

[QueenRefusenik]

A former student of mine got in touch today - she's gone on to start a PhD in Germany and is employed by a research institute and registered as a PhD student with a separate university. She's run into some issues with her supervisor and is asking for advice - if she were at a UK uni I would suggest going to the graduate school/doctoral college or equivalent, or even to her student union, but she doesn't really know what the equivalent might be in Germany. Basically her supervisor/boss seems to be the only person in charge at the institute and she says the university she's technically enrolled in are very hands-off and leave it all to the institute (i.e. her supervisor, who is Prof Silverback in her field and who she really doesn't want to piss off...). I don't really know how to advise her. Is there a German equivalent of Vitae, the research student concordat thingy or codes of practice covering research student supervision she can fall back on, does anyone know?!

[FluctuatNecMergitur]

I have a friend at a German uni, I'll ask her.

[FluctuatNecMergitur]

She says it depends on the uni. PM me which one and she'll look it up in their regulations.