In 1032, a new magistrate was created, called the Provost of Paris, whose duty it was to give assistance to the bourgeois in arresting persons for debt. This functionary combined in his own person the financial and political chief of the capital, he was also the head of the nobility of the county, he was independent of the governor, and was placed above the bailiffs and seneschals. He was the senior of the urban magistracy and police, leader of the municipal troops, and, in a word, the prefect (præfectus urbis), as he was called under the Emperor Aurelian, or the first magistrate of Lutetia, as he was still called under Clotaire in 663. Assessors were associated with the provost, and together they formed a tribunal, which was afterwards known as the Châtelet, because they assembled in that fortress, the building of which is attributed to Julius Caesar.

The Great Châtelet of Paris.--Principal Front opposite the Pont-au-Change.--Fac-simile of an Engraving on Copper by Mérian, in the "Topographia Galliae" of Zeller.