Heritage Days 2026 at Château d'Arnouville (95): the program

It's the must-attend event of September. Heritage Days are once again taking over the Île-de-France region on the weekend of 19 and 20 September 2026 for a 43rd edition packed with discoveries and cultural visits. During this flagship moment on the regional calendar, the general public is invited to discover and rediscover the treasures of Île-de-France heritage.

This event, which takes place all over Europe, is an opportunity to get the most out of a vast program of visits, often free of charge, accompanied by activities designed for young and old alike. In Paris and the Ile-de-France region, a wide range of sites are involved: museums, monuments, castles, churches, libraries and even places that are usually closed to the public, including ministries, embassies and major institutions.

Why not take advantage of this opportunity to explore the heritage of the Ile-de-France region? In the Val d'Oise region, you'll find plenty of great discoveries and cultural nuggets, and in the town of Arnouville, you'll have the opportunity to delve into thehistory of its Château, an unfinished monument built at the end of the 18th century for Jean-Baptiste de Machault d'Arnouville, minister to Louis XV.

• To be read
• This week’s top deals in Paris and Île-de-France, July 27–August 2, 2026

The 2026 Heritage Days program at Château d'Arnouville in Val-d'Oise

• Guided tour of Arnouville Castle and its park

  Built between 1751 and 1757 for Jean-Baptiste de Machault, the Comptroller General of Finances and later Keeper of the Seals for King Louis XV, the Château d’Arnouville features an elegantly proportioned wing, crowned by a chapel and set in a French formal garden. The orangery and its reflecting pool complete the scene. Discover the estate’s history, handed from one owner to another until it became home to a therapeutic, educational, and pedagogical institute.

  Visit offered by the Patrimoines service of Roissy Pays de France, in partnership with ITEP Pierre-Mâle (Entraide Union association).

  Meet at the park entrance, near the orangery. For ages 12 and up.

  Participation guidelines : Free - While seats last - Registration recommended on the Roissy Pays de France website, on the JEP 2026 page - Free | Booking required - 06 11 84 46 47, https://framaforms.org/journees-europeennes-du-patrimoine-2026-visite-du-chateau-et-du-parc-darnouville-dimanche-20-0, https://framaforms.org/journees-europeennes-du-patrimoine-2026-visite-du-chateau-et-du-parc-darnouville-dimanche-20, ecomusee.cartoucherie@roissypaysdefrance.fr, https://www.roissypaysdefrance.fr/actualites/detail/jep2026

  Schedule: Sunday, September 20, 2026 - 2:00 PM ⤏ 3:30 PM, 3:30 PM ⤏ 5:00 PM