Trinquier returned to France in January 1955, being promoted to Lieutenant Colonel and assigned to the staff of General Gilles, commander of the airborne troops. He was posted to Algeria in August 1956 at the airborne base of French North Africa as the war against the FLN was becoming more intense. He then served as second-in-command to General Massu, commander of the 10th Parachute Division, during the Battle of Algiers, where he was one of the leading figures behind the creation of the DPU ("Dispositif de Protection Urbain").