Château d'Aulnois d'Aulnois-sur-Seille, Medieval castle in Aulnois-sur-Seille, France

Château d'Aulnois presents a long pale-ochre stone facade with a projecting central pavilion under a curved pediment and a steep dark slate roof pierced by dormer windows. Three storeys of tall rectangular windows are separated by a lighter stone band, and the right corner steps forward beneath a separate hipped roof. Behind the 18th-century classical building, towers from the 14th and 15th centuries remain integrated into the structure above the Seille.

The castle was rebuilt in 1726 by architect Germain Boffrand for the Count des Armoises, who received the title of Marquis d'Aunoy from Duke Leopold I of Lorraine. This transformation joined medieval structures with Baroque architecture in the service of regional nobility.

Since 1999 the château has housed the public École des Armoises, named after the marquis title granted to the Comte des Armoises in 1726. More than 150 pupils attend class inside the former noble residence, and the Foyer Rural des Armoises association also uses the building for cultural and sporting activities and events.

The château stands in the heart of Aulnois-sur-Seille, above the Seille, and now houses the public École des Armoises; visits are therefore tied to the school's presence rather than to a museum. The medieval towers of the 14th and 15th centuries are visible at the rear of the building, while the 1726 classical facade faces the village side. The Foyer Rural des Armoises, based here, runs cultural and sporting activities and events.

The rear of the château still incorporates towers from the 14th and 15th centuries, remains of the medieval stronghold that belonged to the bishopric of Metz. They were kept when Germain Boffrand rebuilt the house in the classical style in the 18th century.