- French President Raymond Poincare relieves French Commander-in-Chief, General Robert Georges Nivelle of his command following the failure of the Second Battle of the Aisne, also known as the Nivelle Offensive. General Henri-Philippe Petain is appointed as his replacement.
- French army units at Châlons-sur-Marne mutiny following recent defeats and heavy casualties. Outbreaks of mutiny continue until October.
- British troops on the Western Front occupy German trenches south of Oppy