La Conciergerie is a former royal palace and prison in Paris, located on the west of the le de la Cit, near the Cathedral of Notre-Dame. It is part of the larger complex known as the Palais de Justice, which is still used for judicial purposes. Hundreds of prisoners during the French Revolution were executed on the guillotines at La Conciergerie.
The most famous prisoners (and victims) included Queen Marie Antoinette, the poet Andr Chnier, Charlotte Corday, Madame lisabeth, Madame du Barry and the Girondins, who were condemned by Georges Danton, who was in turn condemned by Robespierre, who was himself condemned and executed in a final bout of bloodletting. En route to the tumbrils, the victims walked through the Salle Saint-Louis, (Saint Louis Room), which acquired the nickname of the Salle des Perdus, the 'Room of the Doomed'.
[text via Wikipedia]