A small local museum housed in one of the original 17th-century market pavilions on the central square. The collection centres on the demolished château: stone fragments, architectural drawings, documents related to Cardinal Richelieu's urban planning project, and some period interiors that give a sense of what the original complex looked like before it was broken up and sold off during the Revolution.
The building itself is worth seeing — one of only a few surviving original public structures from the town's founding — and the museum provides useful context for understanding the full scope of what was built here. A modest but well-curated collection.