During the Battle of France, Gabriel Bablon remained stationed in Morocco and did not engaged in any combats. Choosing to pursue combats, he decided to rally to Free France when he was placed in armistice vacation in December 1941. The next month, he was able to join London via Gibraltar and joined the Free French Forces. He was immediately assigned to the 13th Demi-Brigade of the Foreign Legion 13e DBLE in Lebanon. Moved to North Africa with his unit in 1942, he illustrated combat capabilities during the Western Desert Campaign () and was wounded a first time by the blast of a shell in January, then by a mine in June during the Battle of Bir Hakeim (). Heading the second battalion after having been promoted to Chef de bataillon, he distinguished again capability during the Second Battle of El Alamein (). On 23 October colonel Dimitri Amilakvari, regimental commander of the 13e DBLE, was killed and Gabriel Gabon replaced him at the head of the unit. He led the latter during the campaigns of Tunisia () and Italy (). On 17 May 1944, at San Giorgio a Liri, he was wounded again by the blast of a grenade. Disembarked on 31 August 1944 in the disembarking of Provence (), he participated to the Liberation of France (). In September, with the rank of Lieutenant-Colonel, he headed the 24th Infantry Regiment () at the corps of the 10th Infantry Division () commanded by général Pierre Billotte ().