The Cathédrale Notre-Dame stands on the highest point of the old town, a Romanesque foundation later overlaid with Gothic and Baroque additions. The two western towers, the Romanesque crypt, and the Baroque baldachin over the high altar are the highlights.
It was badly damaged by shellfire in WWI and again by bombing in WWII; the restoration is sensitive and the building's complex layers are still legible. The adjoining Cloitre des Chanoines is one of the prettiest small cloisters in the region — usually open at the same hours as the cathedral.