Complex sentence: After the signing of the armistice, France was split into two and the "zone libre" in which the Pyrenees-Orientales was included, came under the administration of the Vichy government.
Split into simpler sentences: After the signing of the armistice, France was split into two. The "zone libre", in which the Pyrenees-Orientales was included, came under the administration of the Vichy government.