Champ de Mars Massacre - Wikipedia

On July 17, 1791, members of the French National Guard under the command of General Lafayette opened fire on s crowd of radical Jacobins at Champ de Mars, Paris, during the French Revolution, killing up to 50 people. From the article:

"The Champ de Mars Massacre took place on 17 July 1791 in Paris in the midst of the French Revolution. The event is named after the site of the massacre, the Champ de Mars. Two days before, the National Constituent Assembly issued a decree that the king, Louis XVI, would retain his throne under a constitutional monarchy. This decision came after Louis and his family had unsuccessfully tried to flee France in the Flight to Varennes the month before. Later that day, leaders of the republicans in France rallied against this decision, eventually leading royalist Lafayette to order the massacre.[1]

Jacques Pierre Brissot, editor and main writer of Le Patriote français and president of the Comité des Recherches of Paris, drew up a petition demanding the removal of the king. A crowd of 50,000 people gathered at the Champ de Mars on July 17 to sign the petition,[2] with about 6,000 having signed the petition. However, earlier that day two suspicious people had been found hiding at the Champ de Mars, "possibly with the intention of getting a better view of the ladies' ankles", and were hanged by those who found them. Jean Sylvain Bailly, the mayor of Paris, used this incident to declare martial law.[3] The Marquis de Lafayette and the National Guard, which was under his command, were able to disperse the crowd.

Later in the afternoon, the crowd, led by Danton and Camille Desmoulins, returned in even greater numbers. The larger crowd was also more determined than the first. Lafayette again tried to disperse it. In retaliation, the crowd threw stones at the National Guard. After firing unsuccessful warning shots, the National Guard opened fire directly on the crowd. The exact numbers of dead and wounded are unknown; estimates range from a dozen to fifty dead."