The Journées du patrimoine are the must-attend event for anyone who wants to swing open the doors of places typically closed or hard to access. For a single weekend, September 19 and 20, 2026, castles, private townhouses, workshops, or institutional buildings reveal their stories and highlight the wealth of Île-de-France’s heritage, often through a free program.
Would you like to take the opportunity to discover the lesser-known heritage of the Paris region? Then head to the château de Bierville, in Boissy-la-Rivière, Essonne. While its current appearance largely dates from the 19th century, the estate has much older roots. The first references to the lordship go back to the 11th century, and only its medieval dovecote still bears witness to that era. The château subsequently underwent several transformations before adopting its present look around 1850.
But Bierville is about more than its architecture. The estate is best known for the role it played in the 20th century, driven by Marc Sangnier, a leading figure in social Catholicism and founder of the Sillon movement. Based on the site from 1921, he organized there in 1926 an international congress devoted to peace and, a few years later, created one of the first French youth hostels. The château also became a haven for refugees fleeing authoritarian regimes in the 1930s.
After the Second World War, the estate kept its mission of transmission and training. It would go on to host union meetings, become a training school, and then the CFDT training center—a role it still fulfills today. This distinctive history makes the Château de Bierville a living heritage, where the values of education, dialogue, and engagement mingle with centuries of Île-de-France history.
Its exceptional opening for the occasion of the Heritage Days offers a chance to discover a site that is rarely accessible, and whose significance extends far beyond its architecture. A wonderful way to cast a fresh light on the heritage of Essonne and Île-de-France.
Discovery tour of the Domaine de Bierville
A stroll through the grounds of the Domaine de Bierville in Boissy-la-Rivière (91690): searching for echoes of the past in a park once owned by Marc Sangnier, the politician and peace advocate of the interwar years.
Participation conditions: Limited seats - Free | Registration required - tourisme@caese.fr, 01 64 94 99 10
Timings: Sunday, September 20, 2026 — 1:45 PM to 2:30 PM, 2:45 PM to 3:30 PM
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Dates and Opening Time
On September 20, 2026
Location
Bierville Castle
château de bierville
91690 Boissy la Riviere
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