A cold email could work - I have done this before with varying success - but I suggest trying to find someone to who can introduce you to a faculty member. Ask your university's German department or study abroad office if they have any contacts there.
If you are active on LinkedIn, another trick to finding contacts is through LinkedIn Advanced Search. Go to Advanced Search and put the name of the university into the "Keywords" field or the in the "Company" field. Then sort the results by "Relationship". You may find that you are connected to someone who is connected to a person working at that university, and voila - you have someone who you can ask for an introduction.