- "We sought to agree on how to put an end to the excesses of the government committees, and to help the National Convention to regain its existence."
- ―Barras on the conspiracy against Robespierre.[src]
In 1792, Barras became a commissioner for the French Army, selling weapons to Philippe Rose. The year after, Barras became acquainted with captain Napoleon Bonaparte at the Siege of Toulon. In 1794, Barras became part of a conspiracy to overthrow Maximilien de Robespierre. When the latter and his supporters fled to the Hôtel de Ville during the Thermidorian Reaction, the National Convention placed Barras in charge of its troops with orders to arrest Robespierre and the Montagnards. Barras proved successful in storming the Hôtel de Ville, and Robespierre was executed the following day. Barras was eventually appointed to command troops in defense of the Convention.
On 13 Vendémiaire in 1795, Royalist forces marched on the Convention, which ordered Barras to take military action against the Royalists, although Napoleon became the de facto leader during the battle. Barras ordered Napoleon to fire on the Royalists with his cannon, ensuring a decisive victory for the Republic. Following this, Barras became the president of the five-man Directory government of France. His tenure was marked by an opulent lifestyle and wild parties, which would later lead to his downfall.
Barras would help Napoleon marry the former's earlier mistress, Joséphine de Beauharnais, in 1796. In 1799 however, Napoleon overthrew Barras and the Directory, proclaiming himself First Consul of France.