I'm from Altenstadt (Alsacia). My grandfather was Joseph Barthel (1909-1981). It's true there is a lot of Barthel and Lutz in this village. Are you sure that Niederseebach is in Germany? It does exist in France, at about 5 km from Altenstadt, but it's true that Alsacia has changed many times concerning the country (several wars between both coutries).