Allied forces for the invasion.
Following the Allied invasion of Normandy the forces of the French Resistance were more formally organized by OSS and SOE agents into the French Forces of the Interior, or FFI. FFI operations were coordinated with Allied tactical plans at the front to cause maximum disruption of German defenses and counterattacks. In the pre-invasion phase of Operation Dragoon, FFI units were instructed to destroy German communications and command and control centers. When the invasion began FFI units were directed to rendezvous with paratroopers and the commandos which landed to guard the flanks of the main invasion force.
The main force was the US Seventh Army, under the command of Guadalcanal veteran Major General Alexander Patch. The Seventh Army was assembled from combat veteran units from the Italian campaign, including VI Corps under Major General Lucian Truscott. VI Corps was involved in long and heavy combat in Italy, and was assigned the role of being the main assault force on the beaches for Operation Dragoon. Seventh Army also contained the French Expeditionary Corps (CEF) which consisted of French, Algerian, and Moroccan troops, veterans of the Italian campaign. Following the assault, French First Army, commanded by Jean de Lattre de Tassigny, was assigned to take the ports of Toulon and Marseille.
The First Special Service Force was assigned to seize the coastal islands of Levant and Port-Cros in the Hyeres Islands. First Special Service Force was a United States – Canadian unit of three regiments, trained in mountain fighting and amphibious assault. Recruiting for the force was aimed at men who had been lumberjacks, hunters, woodsmen, explorers, game wardens, and other outdoorsmen. It was called the Devil’s Brigade, and its men were veterans of fighting the Japanese in the Aleutians and the Germans in Italy. Their mission was to occupy the islands and eliminate the German big guns.
French commandos conducted Operation Romeo the evening before the invasion by the assault forces. The French landed at Cap Negre, west of the invasion beaches, to destroy the German gun emplacements there. A force of less than 100 commandos landed, climbed a 350 foot cliff, and in less than half an hour destroyed the guns. After this success the rest of the commandos landed and a force of 700 established a blocking position across the road to Toulon, preventing a flanking attack on the assault force when it hit the beach. The Germans lost 300 killed and 700 taken prisoner during Operation Romeo.
Operation Dragoon included a deception campaign called Operation Span. Both before the landings and following the assault Operation Span helped keep German units in position by creating the illusion that additional landings were being prepared. Small ships and landing craft approached the French coast in several areas, or cruised just out of range of coastal guns. As in Normandy, fake paratroop drops behind German lines forced the Germans to retain units in their positions rather than use them for counterattacks against the landings. The combination of the commando raids, actions by the Devil’s Brigade, and the deceptions all supported the success of the landings.