That is not quite right. The airport is very close to the France/Germany/Switzerland tri-border and serves the German town of Freiburg (in addition to Mulhouse in France and Basel in Switzerland) but there is no German section in the airport, only a French and a Swiss one. If you want to enter Germany from the airport, you must first enter either France or Switzerland and then cross the border to Germany.

MLH/BSL is the reverse of GVA: GVA is located in Switzerland albeit with a customs road giving direct access to the airport from France without having to enter Switzerland whereas MLH/BSL is located in France albeit with a customs road giving direct access to the airport from Switzerland without having to enter France. As in GVA, you can pick up a car in MLH/BSL either on the Swiss side ("BSL" airport) or the French side ("MLH" airport).