Make the 400 movesis having an unbridled life. During the war led by Louis XIII against Protestantism, the city of Montauban was attacked in 1621 by 400 cannon shots, supposed to bend the inhabitants who were mostly Protestants.
But they did not surrender. The expression stuck and it is said of a person that he "does the 400 blows" when he leads a disorderly life, without respect for customs and traditions.
- Treasures of French expressions by Sylvie Weil. Belin, 2008.
- La Fin des haricots: And other mysteries of French expressions by Colette Guillemard. Omnia, 2009.