Dear @Gordian,
Welcome to the Wefugees Community and thank you for reaching out to us!
In general, the marriage procedure in Germany is not depending on a certain residence status. However, it may get complicated if you can not provide a passport. Please see our blog on this topic for further information on the process and the (usually) required documents. I assume you want to marry in Germany because your partner is living here? In that case, I would recommend you and your partner to contact the local registry office directly and ask for a counselling appointment. Then you will know how they evaluate your situation and which documents you have to submit. Please see also this thread in which a very similar question was raised.
I just remember that we also discussed the marriage procedure in Denmark in a couple of earlier openend threads (here, for instance). Some people may experience the procedure there less complicated. But this just on a side note.
I hope this helps and please do not hesitate to get back to us with any further question.
All the best,
Meike