He served as chief of the staff to the Republican army on the Rhine, but during the Terror he was denounced, arrested, and executed at Paris on June 27, 1794.
Since the old duc de Broglie survived him, the prince de Broglie's eldest son, Victor, eventually became the fourth duc de Broglie. The prince's dying admonition to his little son was to remain faithful to the principles of the French Revolution, however unjust and ungrateful it seemed then to be.