The Conciergerie received its name from "concierge", keeper of the royal palace. Along with the Sainte-Chapelle and the Palais de Justice, it was originally part of the Palais de la Cité, the seat of the kings of France from the 10th century to the mid-14th century, when Charles V abandoned it in favor of the Louvre. By the early 15th century, it was primarily used as a prison, although the name remained.
By the time of the French Revolution, the Conciergerie had become Paris' main prison, with many aristocrats incarcerated there. Nearly 3000 of the prisoners there had been sentenced to death, and one surviving prisoner dubbed it "the vast antechamber of the guillotine". It was also described as "the most lucrative furnished lodging in Paris". The wealthiest prisoners were charged 27 livres a month to rent a bed, but since many were executed within days, jailors could rent out the same bed up to ten times a month.
In an effort to gain favor with Grand Master François-Thomas Germain, the Templar Charles Gabriel Sivert and his associates Arpinon and Duchesneau sought to take advantage of the desperate situation of the nobility and clergy by extorting money and valuables from aristocrats in prisons such as the Conciergerie.
In January 1791, the Assassin Council sent Pierre Bellec and Arno Dorian to the Conciergerie to eliminate Arpinon and acquire a ledger containing Templar records of extorted funds. After eliminating a group of prison guards and sabotaging an alarm bell, the two Assassins eavesdropped on a meeting between Sivert, Arpinon and Duchesneau. Sivert reported that Lord Guillaume de Roussel had agreed to their demands, and as he and Duchesneau left, Arpinon prepared to transport the extorted valuables out of the prison, only to be assassinated by Bellec. Arno then killed Arpinon's bodyguard and stole the ledger, before he and Bellec escaped the Conciergerie.
At some point, the Conciergerie served as the meeting place for a Templar agent and the turncoat Assassin Couillaud. A group of Assassins tailed the latter to the meeting, killed both men and dumped the corpses in the Seine. In 1793, Marie Antoinette, the former Queen of France, was imprisoned at the Conciergerie along with her seven-year-old son, the Dauphin Louis-Charles. The guards locked up the Dauphin on the floor beneath his mother so that she could hear him crying.
During her time in the prison, many of the Queen's captors felt compassion for her, some even bringing flowers. In secret, she plotted with friends of the late Honoré Mirabeau to escape in what became known as the "Carnation Plot". She was to receive a message hidden within the petals of a carnation and pin-prick her response into a piece of paper. The gendarme Jean Gilbert would then bring the message to her allies outside the prison for the sum of 400 louis, equivalent to three years' pay. As Gilbert was secretly a Templar agent, he instead revealed the plot, ensuring that Antoinette would die by the guillotine.
After the deaths of Jacques Pierre Brissot and Olympe de Gouges, their heads were acquired by the politician Lemaitre and the soldier LeNôtre, respectively. The heads were kept within chests at the Conciergerie. Arno stole the key to both chests, and recovered the heads for Marie Tussaud, who had been tasked with sculpting death masks from them. The Conciergerie would also hold sixteen Carmelite nuns accused of opposing the revolution, who were guillotined in July 1794.