For the Journées du Patrimoine 2026, the musée du Vexin français in Théméricourt in the Val-d'Oise invites you on a revitalizing cultural outing. Each autumn, this event invites residents of Île-de-France to swing open the doors of emblematic or unusual places in Paris and across the Île-de-France, often free or at a preferential rate. On the 19 and 20 September 2026, the rendezvous is set to explore the Francilian heritage in a new light.
Housed in the refurbished ancient outbuildings of Théméricourt Castle, the museum is the beating heart of the Maison du Parc naturel régional du Vexin français. Erected at the close of the 15th century under the patronage of Philippe de Théméricourt, the building exemplifies the early French Renaissance, a period marked by the gradual abandonment of medieval defenses in favor of residential elegance: an L-shaped layout, mullioned windows, and four slender pepperpot turrets at the corners. Local legends long whisper of hidden tunnels that still link the manor’s vaulted cellars to the surrounding woods.
Far from being just a postcard backdrop, the museum aims to tell the story of the people and the unique geology of the Vexin limestone plateaus. The permanent route explores traditional stone-built homes with thatched roofs, centuries-old agricultural tools, and the wildlife of the wetlands in the Aubette de Meulan valley. Below you'll find the details of the tours and activities planned for this special weekend.
Archi'Vexin, exploring the heritage of the French Vexin
For those who wander through the French Vexin, the villages quickly feel like old friends. Stone houses, tiled roofs, farms tucked into the heart of the towns, washhouses along the waterways... This preserved architecture is what gives the region its distinctive charm. The Archi’Vexin exhibition will reveal all its secrets: what exactly characterizes a farm? Which techniques were used to build churches? What materials went into the construction of houses? Come discover the answers and much more at the Musée du Vexin français!
Across nine themes enriched with scale models, hands-on activities and games, explore the built heritage of the French Vexin and trace its evolution. Whether you're an aspiring builder, a budding heritage conservator, a longtime resident, or simply a curious visitor, young or old, this exhibition welcomes everyone and is free to attend during European Heritage Days.
Participation conditions: Free | No reservation required
Hours: Saturday, September 19, 2026 — 09:30 to 12:30, 14:00 to 18:00 | Sunday, September 20, 2026 — 10:00 to 18:00
Conference: Astonishing houses and fine estates in the French Vexin
Discover remarkable vacation homes and other architectural fantasies with the help of Marianne Metais, a researcher in the regional heritage inventory of Île-de-France, and Luc-Olivier Baschet, a member of the AVRIL association.
Participation requirements: Free admission | Booking required - https://www.billetweb.fr/pro/museevexin, 0134486600
Schedule: Sunday, September 20, 2026 — 2:00 PM to 3:00 PM
Quick tours of the Archi'Vexin exhibition
Archi'Vexin is an interactive, playful exhibition that invites visitors to explore the architecture and heritage of the French Vexin. In the afternoon, a guide-lecturer leads three quick 30-minute tours of the exhibition, offering a concise overview and a chance to ask any questions.
Conditions de participation : Free | No reservation required
Schedule: Sunday, September 20, 2026 — 2:30 PM–3:00 PM, 3:30 PM–4:00 PM, 4:30 PM–5:00 PM
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Dates and Opening Time
From September 19, 2026 to September 20, 2026
Location
The French Vexin Museum
2-4 Rue Achim d'Abos
95450 Themericourt
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