Mace joined the army on 21 October 1915. On 22 July 1917, he transferred from an artillery regiment to the French Air Service. After receiving a Pilot's Brevet, he was assigned to Spa90 and downed 4 enemy aircraft and 8 balloons by the end of the war.
"Self-sacrificing, audacious, and unselfish pilot who is an excellent example to all. He has returned sixteen times with his clothes and aircraft shot through by enemy fire. He has destroyed two planes and one balloon. On 22 September , he reported two new victories by flaming two enemy observation balloons. Four citations." Médaille Militaire citation