Thank you - this was my next question. I found this on the previously provided website: "Before traveling, you should make inquiries at your local competent office of public order if you have any doubts about the breeds of dog classified as dangerous or about the documents required."
What is the local competent office of public order? Would that be the German Federal Police?
No, it is the „Ordnungsamt“. The authority in Germany for everything which is concerning public safety but isn‘t to full of action. They are keeping an eye on parking in the right places, the height of fences, if the neighbours are quiet enough and on the dogs (and much more). A Friends of mine keeps calling them „the most german authority“.
But they aren‘t federal. Your problem is the federal law. So I would stay with customs and/or the „Bundespolizei“