Hi Matthias
I think the challenge here is whether members are in a position to close such information (confidentiality, etc). You might have more success searching job boards to see if a bank in Germany happens to be recruiting for GRC skill set.
Also, if you explain a little bit about what you are doing bench marking(is this research or work related, etc) for, and update your personal profile with contact details you might have someone reach out to your privately to discuss.
Regards
Colleen