Flameng later received renown for his painting of World War I. He was named honorary president of the Society of Military Painters and an accredited documenter for the War Ministry. His work was displayed in the Hôtel des Invalides in Paris, as well as being reproduced in newsmagazines. At the time they were painted, Flameng's war paintings were derided by many critics for being too realistic and not including heroic drama (although his paintings seem romantic to eyes which have seen photographs of genocide and nuclear war).