The 3rd arrondissement of Paris, situated on the right bank of the River Seine, is the second smallest in area after the 2nd arrondissement. The arrondissement contains the northern, quieter part of the medieval district of Le Marais (while the 4th arrondissement contains Le Marais' more lively southern part, notably including the gay district of Paris). The oldest surviving private house of Paris, built in 1407, is to be found in the 3rd arrondissement, along the rue de Montmorency.

A small but rapidly expanding Chinatown inhabited by immigrants from Wenzhou centers on the rue au Maire, near the Conservatoire National des Arts et Métiers housed in the medieval priory of Saint-Martin-des-Champs.