The Sacred Heart was, in fact, invoked during this conflict by millions of faithful Catholics, but was never placed on the Flag. In fact, the image of the Sacred Heart, was broadcast very widely. Millions of copies were distributed. It was commonly found in the trenches, to the point that a circular from the Minister of War of 6 August 1917 (countersigned by Philippe Pétain later the president of unoccupied France in 1940) prohibited its exhibition.
The Corps of Marechal Foch, soon after placing the Sacred Heart on the 20th corps flag were instumental in the repulse of the Germans at the battle of 2nd Marne. Roert Nivelle troops mutinied in 1917.