In 1791, he became vice-president of the criminal tribunal of Paris. Re-elected to the Convention, he was sent to Normandy, where he directed bitter reprisals against the supporters of Federalism.
He voted for the death of KingLouis XVI, and as a member of the Committees of National Defence and of Public Safety he was despatched in October 1793 to Brittany, where he established the local version of the Reign of Terror. In May 1794 he became president of the Convention. The Thermidorian Reaction drove him into hiding from May 1795 until the amnesty proclaimed in the autumn of that year.