Army Group 1 (, GA 1) was the primary French Army maneuver formation during the Battle of France. Headquartered in Bondy, it was historically significant as the command responsible for the execution of the Dyle Plan (Plan D) and controlled the most modern motorized and mechanized wings of the Allied forces. Under the command of Gaston Billotte, it defended the critical sector between the English Channel and the northern terminus of the Maginot Line.
During the campaign of May 1940, GA 1 exercised operational command over the specialized Cavalry Corps and the British Expeditionary Force (BEF) under General Lord Gort. Following the German breakthrough at Sedan, GA 1 was central to the Allied attempt to contain the encirclement of the northern forces.
The following formations were subordinate to the French 1st Army Group at the start of the German invasion, based on official TOSE and GUF records: