The Marquis de Lafayette ordering his men to fire on the crowd
The Champ de Mars massacre occurred on 17 July 1791 when the French National Guard, commanded by the Marquis de Lafayette, fired on a crowd of 50,000 Parisian protesters as they marched through the Champ de Mars with a petition demanding King Louis XVI of France's removal; killing anywhere from 12 to 50 people. Jacques Pierre Brissot had authored the petition in response to the Flight to Varennes, and Mayor Jean Sylvain Bailly declared martial law, raising red flags to warn the protesters. The massacre would lead to increased republican sentiment, as well as Bailly's execution during the Reign of Terror two years later.