​​Born 29 April 1904 in Caen, Léonard Gille became a lawyer before making himself known prewar for his political involvement in the ranks of the Radical Party.

​He was mobilised in September 1939 in the 3rdzRégiment du Train as reserve Captain. He returned to Caen after the fall of France and occupation by Nazi Germany, having fought on the Maginot Line. Gille returned to his profession as a lawyer before joining the Resistance in a small group that includieda former combat comrades like René Duchez, Léon Dumis and André Masseron.

On 1 July 1941, Gille joined the Volunteer Army, which in spring 1942 joined the Civil and Military Organisation (OCM) and the Centurie network in Caen. Within the OCM, Gille became assistant to Eugène Meslin, Chief of Staff of Marcel Girard, head of the organisation for Normandy. With the pseudonym ‘Marie’, Gille also took care of the ‘Marie-Odile network’ along with his partner and future wife, Louise Boitard, known as ‘Janine’. The ‘Marie-Odile network’ was an escape network specialised in the clandestine convoy of Allied pilots shot down, across France.

​Gille ceased his legal profession in March 1943. In September 1943, he represented the Radical Party on the Departmental Committee for Clandestine Liberation, of which he was elected president. Following a wave of arrests and repression in late 1943, Gille was wanted by German forces and had to move away from the Calvados region and go underground.

​The Allied landings surprised him while he was in Paris. Having head urgently back to Calvados, Gille received word from Meslin: this was the mission to ensure his place as commander of subdivision M1 (Calvados, Manche, Eure) of the FFI. Gille moved his staff near Frénouville, before returning to Caen where he set up company FFI ‘Fred Scamaroni’. This was led by Georges Poinlane, who fought alongside the Allies during the liberation of the city.

On 20 July 1944, once Caen was finally liberated, Gille officially convened the Committee for the Liberation of Calvados. He chaired this until its dissolution at the end of 1945. In December 1944, he was elected vice-president of the Radical Socialist Party. He was raised to the rank of Colonel, and elected Councillor General of the canton of Bourguébus in September 1945. He remained Vice-President of the Departmental Assembly until his death in Caen on 23 January 1971. Louise Boitard, his wife, died 30 years later in 2001. Gille is buried in the hamlet of Poirier, in Frénouville.