I think it would be right to contact the German authorities. So there will not be any unpleasant surprises at the airport.
I would try the German Federal Police, formerly the German border patrol. They should know.
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?