Built prior to World War II, Istres Air Base was first used by the French Air Force during the early part of the war, and after the 1940 Battle of France and the June Armistice with Nazi Germany, became part of the limited () air force of the Vichy Government. It was attacked on several missions by Allied bombers based in England while under German control after November 1942. It was seized by Allied forces during Operation Dragoon, the Invasion of Southern France in August 1944 and was repaired and placed into operational use by the United States Army Air Forces XII Engineer Command, being turned over to Twelfth Air Force on 27 August 1944.