The French Underground, also known as the Maquis, was a group of French resistance fighters during World War II. They were active in the fight against Nazi Germany and its collaborators, and their efforts helped to liberate France from German occupation. The term 'Maquis' is derived from the French word for scrubland, and it was used to describe the rural areas where the French Underground operated. The Maquis were organized into small, independent groups that conducted guerrilla warfare against the Germans. They carried out sabotage operations, ambushes, and other acts of resistance.