Château de Montaigu sits just outside Nancy in Laneuveville-devant-Nancy, close to the grounds of the former royal estate at Montaigu. The house is best known for its early-20th-century interiors and collections, which connect naturally with Nancy's Art Nouveau story and the wider decorative-arts tradition of Lorraine.
It is a quieter stop than the city's headline museums, so check opening times before going. For travellers interested in furniture, ceramics, domestic interiors, and the Belle Époque world that produced the École de Nancy, the château adds a useful country-house counterpoint to the urban Art Nouveau route.