Between 1,176 and 1,614 people[1] were killed by sans-culottes, fédérés, and guardsmen, with the support of gendarmes responsible for guarding the tribunals and prisons,[2] the Cordeliers, the Committee of Surveillance of the Commune, and the revolutionary sections of Paris.

[3][4][5] With Prussian and royalist armies advancing on Paris, and widespread fear that prisoners in the city would be freed to join them, on 1 September the Legislative Assembly called for volunteers to gather the next day on the Champs de Mars.

[6] On 2 September, around 1:00 pm, Minister of Justice Georges Danton delivered a speech in the assembly, stating: "We ask that anyone refusing to give personal service or to furnish arms shall be punished with death.

[14][15] The identity of the perpetrators, called "septembriseurs", is poorly documented, but a large number were Parisian national guards and provincial federates who had remained in the city since their arrival in July.

[19][20] Danton was also accused by later French historians Adolphe Thiers, Alphonse de Lamartine, Jules Michelet, Louis Blanc and Edgar Quinet of doing nothing to stop them.

His avowed aim was to put an end to the anarchy in the interior of France, to check the attacks upon the throne and the altar, to reestablish the legal power, to restore to the king the security and the liberty of which he is now deprived and to place him in a position to exercise once more the legitimate authority which belongs to him.

[28] The commune pushed through several measures: universal suffrage was adopted, the civilian population was armed, all remnants of noble privileges were abolished and the properties of the émigrés were sold.

These events meant a change of direction from the political and constitutional perspective of the Girondists to a more social approach given by the commune as expressed by Pierre-Joseph Cambon: "To reject with more efficacy the defenders of despotism, we have to address the fortunes of the poor, we have to associate the Revolution with this multitude that possesses nothing, we have to convert the people to the cause.

[31] To ensure that there was some appropriate legal process for dealing with suspects accused of political crimes and treason, rather than arbitrary killing by local committees, a revolutionary tribunal, with extraordinary powers to impose the death sentence without any appeal,[32] was installed on 17 August.

[35] Marat left nothing in doubt when he urged "good citizens to go to the Abbaye, to seize priests, and especially the officers of the Swiss Guards and their accomplices and run a sword through them".

Roland proposed that the government should leave Paris, whereas Robespierre suggested in a letter to the sections of the commune that they should defend liberty and equality and maintain their posts, and die if necessary.

At the behest of Justice Minister Danton, thirty commissioners from the sections were ordered to search in every (suspect) house for weapons, munition, swords, carriages and horses.

[49] The bulk of the butchers were made up of "Marseilles," "hired assassins" from the prisons of Genoa and Sicily, paid twenty-four dollars, whose names were listed by "M. Granier de Cassagnac.

[55] On 2 September, around 13:00, Georges Danton, a member of the provisional government, delivered a speech in the assembly: "We ask that anyone refusing to give personal service or to furnish arms shall be punished with death.

[62] The first massacre began in the quartier Latin around 2:30 pm on Sunday when 24 non-juring priests were being transported to the prison de l'Abbaye near the Abbey of Saint-Germain-des-Prés, after being interrogated by Billaud-Varenne in the town hall.

[64] In the late afternoon 115 priests in the former convent of Carmelites, detained with the message they would be deported to French Guiana, were massacred in the courtyard with axes, spikes, swords and pistols by people with a strong patois accent.

[73] All ten former members of the royal household were placed before the tribunals and freed from charges, with the exception of the Princess de Lamballe,[74][75] whose death would become one of the most publicized of the September Massacres.

Late in the afternoon, they went to Tour Saint-Bernard (belonging to a confiscated monastery Collège des Bernardins, located in the Sansculotte district) where forgers of assignats were jailed.

Police commissioners Etienne-Jean Panis and Sergent-Marceau gave orders to wash away all the blood from the stairs and the courtyard, to spread straw, to count the corpses, and to dispose of them on carts to avoid infections.

[105][106]Though it is an ascertained fact that the perpetrators of the atrocious murders were but a few; yet it is not so clear that this work was not connived at, or consented to, by a much greater number, and those perhaps in authority; for otherwise, two or three companies of the town guard would have been sufficient to disperse those who were employed on the occasion.

[111]Rather than being proof of the unprecedented depravity of an entire population, the prison massacres were the explicable result of both the "wrath and fury" of the victims of 10 August and the machinations of the Paris Commune, who gave their tacit consent to the killings.

In a similar way to Perry, Williams emphasizes the understandable impatience of the people, who had been kept waiting too long for justice after the August Days, when husbands, brothers, and fathers had been killed.

[94][121] After initially indiscriminate slayings, ad hoc popular tribunals were set up to distinguish between "enemies of the people" and those who were innocent, or at least were not perceived as counter-revolutionary threats.

[18] On 3 September the surveillance committees of the Commune, on which Marat now served, published a circular that called on provincial Patriots to defend Paris and asked that, before leaving their homes, they eliminate counter-revolutionaries.

[123] A circular letter was sent to regional authorities by Deforgues, an assistant of Danton, and Tallien, the secretary of the Paris Commune, advising that "ferocious conspirators detained in the prisons had been put to death by the people".

Most notable was the killing of 44 political prisoners near Château de Versailles transported from the High Court in Orléans back to Paris, the 9 September massacres.

"[130] On 1 September the Commune declared a state of emergency by decreeing that on the following day the tocsin should be rung, all able-bodied citizens convened in the Champ de Mars.

Accordingly, there was no attempt to assuage popular fears that the understaffed and easily accessed prisons were full of royalists who would break out and seize the city when the national guards and other citizen volunteers had left for the war.

The other members of the provisional government – Clavière, Lebrun-Tondu, Monge and Servan, involved in organizing the country did not do much to stop the killing, or could not foresee or prevent these excesses.

Jean-Baptiste Louvet de Couvray accused Robespierre of creating a personality cult, governing the Paris "Conseil General" and paying the "Septembriseurs".