Now owned by the Hôtel de Carondelet, these medieval cellars, which predate the construction of the Mont de Piété, cover an area of about 100m² and three levels corresponding to several periods of construction. At the deepest level we will find ourselves 10m below the level of the current road in what was during the Second World War an anti-aircraft shelter, and in a world of sandstone bearing the marks of its successive occupations. Between the second and third levels is a remarkable and wide hallway-staircase covered with 17 sandstone vaults, which is unique in Valenciennes. Visits by groups of 10 people and organization can be modified according to the sanitary constraints of the moment. No free visit.