La Conciergerie is a former royal palace and prison in Paris, France, located on the west of the Île de la Cité, 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 taken from La Conciergerie to be executed on the guillotine at a number of locations around Paris.
The Middle Ages:
Le Palais west part of the island was the site of a Merovingian palace; and from the 10th to the 14th centuries was the seat of the medieval Kings of France. Under Louis IX (Saint Louis) (1226-1270) and Philip IV (1284-1314) the Merovingian palace was extended and more heavily fortified.