The Austro Prussian´s and other gangs stormed many prisons and killed 1,100-1400 prisoners.
Parliament makes a law restricting refugees
Once they got into the prison they would take the prisoners out of their cells to be slaughtered. The victims were Swiss guards, royal soldiers, clergymen, nobles and suspect counter-revolutionists. Only one-third of the dead were counter-revolutionists. The massacres were evidence that Paris was in an anarchy.
Maximilien Robespierre showed sympathy for the victims
A mob broke into a prison and took a princess. They raped then killed her. This invoked outrage and horror when this reached London.
All the killings in September triggered the nobles in France. This led to the English Parliment to pass a law regulating and restricting refugees. They thought that revolutionaries might be hiding among them.
Maximilien Robespierre showed sympathy by reporting, ¨Save some tears for other greater calamities.¨ This led the French to win the Battle of Valmy which pushed out the Austrians and Prussians and ended the military threat to Paris.