The Palais de la Cité (palɛ d(ə) la site), located on the Île de la Cité in the Seine River in the centre of Paris, is a major historic building that was the residence of the Kings of France from the sixth century until the 14th century, and has been the center of the French justice system ever since, thus often referred to as the Palais de Justice. From the 14th century until the French Revolution, it was the headquarters of the Parlement of Paris. During the Revolution it served as a courthouse and prison, where Marie Antoinette and other prisoners were held and tried by the Revolutionary Tribunal. Since the early 1800s it has been the seat of the Tribunal de grande instance de Paris, the Court of Appeal of Paris, and the Court of Cassation. The first of these moved to another Parisian location in 2018, while the other two jurisdictions remain located in the Palais de la Cité as of 2022.
The palace was built and rebuilt many times over the course of many centuries, including following major fires in 1618, 1776 and 1871. Its salient medieval remains are the Sainte-Chapelle, a masterpiece of Gothic architecture, and the Conciergerie, an early-14th-century palatial complex that served as a prison from 1380 to 1914. Most of its other current structures were rebuilt from the late 18th to early 20th centuries. The Conciergerie and Sainte-Chapelle can be visited via separate entrances.
Archeological excavations have found traces of human habitation on the Île de la Cité from 5000 BC until the beginning of the Iron Age, but no evidence that the Celtic inhabitants, the Parisii, used the island as their capital. Julius Caesar recorded meeting with the leaders of the Parisii and other Celtic tribes on the island in 53 B.C., but no archeological evidence of the Parisii has been found there. However, after the Romans conquered the Parisii in the first century BC, the island was developed quickly. While the forum and largest part of the Roman town, called Lutetia, was on the left bank, a large temple was located on the east end of the island, where the Cathedral of Notre Dame de Paris is found today.