After the French Revolution, Levasseur served on the municipal government of Le Mans in 1790 and the district government in 1791. In the 1792 election to the new National Convention he won a seat representing the département of Sarthe. At the 1793 trial of Louis XVI , Levasseur voted in favour of his execution. He supported the creation of the Revolutionary Tribunal and was among the fiercest opponents of Modérantisme, especially in the insurrection of 31 May – 2 June 1793, supporting the arrest of all Girondins. He served in the Army of the North and his horse was shot from under him at the Battle of Hondschoote. He was tasked with restoring order in Beauvais and Oise, but was considered too moderate and André Dumont was sent to assist him. Maximilien Robespierre replaced him in November 1793 when disturbances erupted in Gonesse.