The town hall was rebuilt in 1675 according to plans drawn up by Hardouin-Mansart, but the Arles-born architect Peytret preserved the previous building's 16C clock tower, which was inspired by the mausoleum of the Plateau des Antiques in St Rémy. The vault in the vestibule is almost flat and is considered a true masterpiece. The construction of the two keystones still remains a mystery for architects.