As an anecdote I know from my nephew who is a BMW egineer that went to Germany for training. He took his family. His girls went to the American School. Although not segregated, there was an “American Community”
Yes, there is an American community. It developed during 40 years of the Cold War, when 250,000 US troops were in Germany. We were there for only 2 or 3 years and then came home. Some GIs were “barracks rats” who never left post, others of us got out and traveled and learned a functional level of German to get around when traveling. Some guys never got beyond “Bier, bratwurst, pommefrites, and schnitzel.” And looking for that mysterious town of Ausfahrt one saw the signs for on the autobahn.