Louis was officially arrested on August 13, 1792 and sent to the Temple, an ancient Paris fortress used as a prison. On 21 September, the National Assembly declared France to be a republic and abolished the monarchy.

The Girondins were partial to keeping the deposed king under arrest, both as a hostage and a guarantee for the future. The more radical members – mainly the Commune and Parisian deputies who would soon be known as the Mountain – argued for Louis's immediate execution. The legal background of many of the deputies made it difficult for a great number of them to accept an execution without due process of some sort, and it was voted that the deposed monarch should be tried before the National Convention, the organ that housed the representatives of the sovereign people.

On 11 December, among crowded and silent streets, the deposed king was brought from the Temple to stand before the Convention and hear his indictment, an accusation of High Treason and Crimes against the State. On 26 December, his counsel, Raymond de Sèze, delivered Louis's response to the charges, with the assistance of François Tronchet and Malesherbes.