Complex sentence: In 1946, the administration of the French zone of occupied Germany made an area of in the German part of the Upper Mundat Forest administratively a part of France, in order to guarantee the water catchment area for Wissembourg.
Split into simpler sentences: In 1946, the administration of the French zone of occupied Germany made an area of in the German part of the Upper Mundat Forest administratively a part of France. This was in order to guarantee the water catchment area for Wissembourg.