Did you know that just a few kilometres south of Paris lies a property usually closed to the public, where grand history has been put to work for solidarity? For the Heritage Days 2026, which takes place the weekend of September 19 and 20, 2026, the municipality of Épinay-sur-Orge in Essonne has a tasty surprise in store: the exceptional opening of the Sillery estate. This annual autumn rendezvous invites curious visitors to explore Paris and Île-de-France’s hidden treasures, and this address ticks all the boxes for off-the-beaten-path discovery.
The estate immediately impresses with its sprawling park, several hectares in size, registered as a Historic Monuments site. Designed in 1837 by Louis-Sulpice Varé — the renowned landscaper later entrusted by Napoleon III with the redevelopment of the Bois de Boulogne — the grounds embody the art of English Romantic gardens.
Unlike the straight lines and rigid geometry of classical French formal gardens, the landscape style highlights a reinvented nature: sinuous artificial contours, wooded islets, waterfalls, an artificial grotto, and water features linked by an ingenious hydraulic network. The walk gives the impression of a wild landscape, yet it is precisely measured. According to some local chronicles, underground galleries would even connect the estate's cellars to old outbuildings in the valley, though excavations have never been able to confirm this tale.
In the heart of the greenery stands the Château de Sillery. Restyled around 1860, the residence embraces the sober lines of 19th-century neoclassical and eclectic architecture, recognizable by its orderly façades, tall windows, and a Mansard roof pierced by elegant dormers.
But the true hallmark of the estate lies in its human vocation. Owned by the Franco-British Foundation of Sillery, born in the wake of World War I in 1919, the site is not a simple monument frozen in time. Today it houses medico-social facilities dedicated to supporting and training young people and adults with disabilities. Visiting Sillery thus means viewing a living heritage where the preservation of the natural setting and social utility intersect daily. A delightful Île-de-France escape to slip into your weekend plans without hesitation. Discover now the on-site activities and guided tours planned there:
Tour of the Sillery estate
For European Heritage Days, immerse yourself in the history of the Sillery Foundation's estate, home to the Franco-British Foundation.
Follow a history-keen guide to discover this romantic park, a true 19th-century masterpiece. In 1837, landscape architect Louis-Sulpice Varé transformed the property into a haven of poetry: cascades whispering among the trees, a mysterious grotto, wooded islets and glimmering basins. Between 1860 and 1867, the park was enhanced with canals and water features, while the 1880s saw the birth of a fish farm and a cress house.
The Franco-British Foundation of Sillery is a living space dedicated to inclusion and to supporting people with disabilities or those in vulnerable situations. Come stroll through the gardens, admire the château's architecture, and hear the story of a place where nature, heritage and solidarity come together.
Exceptional access to the château chapel is possible after the visit.
This visit involves walking, so you should be in good shape to participate and wear appropriate footwear.
Registration required at: www.destination-paris-saclay.com
Participation terms: Limited to 30 people per time slot — Free | Reservation required - https://www.destination-paris-saclay.com/fr/fiche/fete-et-manifestation/visite-du-domaine-de-sillery-epinay-sur-orge_TFO7912022/
Schedule: Saturday, September 19, 2026 — 10:00–11:00, 11:30–12:30, 14:00–15:00
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Dates and Opening Time
From September 19, 2026 to September 20, 2026
Location
Sillery Franco-British Foundation
2 Rue de Charaintru
91360 Epinay sur Orge
Route planner
Official website
www.fondationfrancobritannique.com
