The 19 and 20 September 2026, culture is also back in the spotlight for the Heritage Days! The year’s must-attend cultural event returns to deliver a hearty dose of activities, workshops, and guided tours at the heart of Europe’s finest historic addresses. Across Île-de-France, the Heritage Days bring together a multitude of sites open to the public for free, inviting visitors to delve into the region’s fascinating history. Explore sumptuous castles, discover charming preserved villages, or visit iconic museums and monuments, all offering their own surprises. Let yourself be swept up in this cultural adventure, a true celebration of Île-de-France’s heritage!
Take advantage of the Heritage Days 2026 to escape the capital and explore the vast reaches of Île-de-France, including the charming town of Conflans-Sainte-Honorine, in the Yvelines. Founded in the XIIth century, the town flourished over time thanks to its strategic position on the banks of the Seine. The authentic charm of its cobbled streets transports you to the medieval era, while its impressive castles and churches stand as enduring monuments to its rich heritage. In the 19th century, Conflans-Sainte-Honorine became a key inland port, buzzing with commerce and its traditional bateaux-mouches. Today, the town continues to captivate visitors with its picturesque ambiance and a wealth of sights to discover on foot or by water.
Heritage Days 2026: discover the Canal Boatmen Museum in Conflans-Sainte-Honorine (78)
They're back: this weekend, Saturday, September 19 and Sunday, September 20, 2026, the Heritage Days kick off a new edition in Paris and Île-de-France. Over in Conflans (78), head to the Museum of River Barging and Inland Waterways! [Read more]
Heritage Days 2026 at Château de Themericourt
Exhibition: “Remarkable Beacons”
“Remarkable Beacons” is a maritime term describing built or natural landmarks, often repainted, visible as you approach the shore and used as reference points to plot a navigational course.
Driven by the collective Dans le Sens de Barge, this group exhibition showcases about sixty artistic proposals conceived from the river in motion, from the estuary to the far reaches of Île-de-France. The result is a collection of possible artistic beacons—poetic or utopian.
Locations: Pointil, the castle’s iron gates, and Place Fouillère, sites on public land, freely accessible and outdoors.
Participation requirements: Free | No reservation required
Opening hours: Friday, September 18, 2026 - 09:00 ⤏ 19:00 | Saturday, September 19, 2026 - 09:00 ⤏ 19:00 | Sunday, September 20, 2026 - 09:00 ⤏ 19:00
Heritage Days 2026 at Château du Prieuré – Winter Garden
Craftsmanship by the Conflanais Creative Collective
Exploring local craftsmanship and meeting the artisans of the Conflans Creative Collective.
Participation requirements: Free admission - No reservation required
Hours: Saturday, September 19, 2026 – 10:30 AM to 6:30 PM | Sunday, September 20, 2026 – 10:30 AM to 6:30 PM
Heritage Days 2026 at the Priory's Grand Cellar
Guided Tour of the 13th-Century Grand Cellar
Exceptional opening of the great 13th-century cellar, an architectural relic of the former priory normally closed to visitors. Now housing the collection of pleasure boats at the Museum of Inland Waterways, this site, with its preserved architecture, stands as a patrimonial showcase of notable interest.
Participation conditions: Free admission - No reservation required
Hours: Saturday, September 19, 2026 – 10:00–19:00 | Sunday, September 20, 2026 – 10:00–19:00
Heritage Days 2026 at the Greenhouse of Priory Park
Exhibition "A Prix de Rome in Conflans"
The association Conflans Through the Ages (CATLA) will showcase the highly varied body of work by Raoul Raba, a Prix de Rome laureate, two of whose sculptures adorn the park: The Lovers and The Cinema. The association will also present its historical publications.
Participation conditions: Free admission - No booking required
Hours : Saturday, 19 September 2026 — 10:00–19:00 | Sunday, 20 September 2026 — 10:00–19:00
Heritage Days 2026 at Saint-Maclou Church
Guided tour of Saint-Maclou Church
The Conflans Through the Ages Association (CATLA) invites you to discover the church’s history, its heritage treasures, and the latest restoration work, unveiling to the public the traces of its past.
Participation requirements: Free | No booking required
Schedule: Sunday, September 20, 2026 - 3:00 PM ⤏ 3:40 PM
A concert by the conservatory's faculty
Concert by the conservatory's faculty, organ and trumpet
Participation conditions: Free | No reservation required
Schedule: Sunday, September 20, 2026 — 6:00 PM to 7:00 PM
Heritage Days 2026 at City Hall
City Hall: An Introduction
To mark the 130th anniversary of the Town Hall, which opened on 19 July 1896, the Archives and Documentation Service invites you to explore the history of the buildings that make up the "house of the commune." From the location of town halls to the architectural style, and through its evolution (integration of the former girls’ and boys’ schools, relocation of services across the territory), this presentation will culminate with the town hall as an institution, its development, the mayor’s role within the city, and the municipal elections.
Participation terms : Free | Booking required - archives@mairie-conflans.fr
Schedule: Sunday, September 20, 2026 — 10:30–11:45, 14:00–15:15
Heritage Days 2026 at the old Freight Exchange
Old Chartering Exchange
Discover the story of the Freight Exchange Building (now home to the Territorial Service Boucles de la Seine of Voies Navigables de France), perched on land prone to floods and built on stilts—a true inheritance of the Modernist principles championed by Le Corbusier. In 1959, with traffic on the rise and a desire to project faith in progress, the National Navigation Office entrusted the design of the current building to architects Xavier and Luc Arsène-Henry, Rome Prize winners and leading figures of the Modern Movement.
Terms of participation: Free | Booking required - culture@mairie-conflans.fr
Schedule: Saturday, September 19, 2026 - 2:00 PM ⤏ 3:00 PM, 3:30 PM ⤏ 4:30 PM | Sunday, September 20, 2026 - 11:30 AM ⤏ 12:30 PM
Heritage Days 2026 at Montjoie Tower
Guided tour of Old Conflans
A guided tour of the old town, exploring its history and architectural heritage, will take you from Tour Montjoie, past Saint-Maclou Church, to the viewpoint at Terrasse Gévelot—a delightful stroll ahead.
Participation terms: Free of charge | Booking required - contact@terres-de-seine.fr
Schedule: Saturday, September 19, 2026 — 3:30 PM to 5:00 PM
Heritage Days 2026 – Cruises offered by the Tourist Office
Guided heritage cruise
On a cruise ship, discover from a fresh perspective the town of Conflans-Sainte-Honorine and its history, inextricably tied to the river and to the inland navigation trade.
Participation conditions: On-site reservation in the Terres de Deine Tourism Office van, François Mitterrand Promenade opposite the landing dock. - Free | Reservation required - 07 66 48 61 55
Schedule: Sunday, September 20, 2026 — 3:00 PM–3:45 PM, 4:00 PM–4:45 PM, 5:00 PM–5:45 PM
Le programme est mis à jour en fonction des annonces officielles.
Heritage Days 2026 at Repos Cemetery
Aucun événement annoncé à ce jour, le programme est mis à jour en fonction des annonces officielles.
Heritage Days 2026 on Île de Devant
Visit to Devant Island
Discover Devant Island and its exceptional natural and historical heritage: wildlife, preserved flora, and remnants of the past. From its paved paths, enjoy a striking panorama of Conflans-Sainte-Honorine, with views of the Montjoie Tower, Saint-Maclou Church, and the Prieuré Castle.
Accessible by Conflanette from the town center, the island is best explored on foot along a forest trail lined with benches and educational panels dedicated to biodiversity and environmental protection.
Don’t miss the former Shell building, now repurposed as a bat roost and enhanced by a monumental fresco from artist Dzia depicting these fascinating mammals.
Participation terms: Free of charge | Booking required - http://www.terres-de-seine.fr
Hours: Saturday, September 19, 2026 – 12:45 PM ⤏ 4:45 PM | Sunday, September 20, 2026 – 12:45 PM ⤏ 4:45 PM
Heritage Days 2026 at Parc du Prieuré
Coats of arms reimagined: video projection set to music
The Circle of the Galactic Orbit (an association dedicated to playful and digital art) is developing a video-mapping installation for Prieuré Park, drawing on the city’s coat of arms—as seen on the park’s stairway reliefs near the Rue Pasteur entrance. As part of the project, the association will integrate the coats of arms created by a group of local after-school kids into the piece. It’s a chance to introduce them to digital arts!
Participation conditions: Screening projected on the park staircase bas-reliefs (entrance on the Pasteur Street side) — Free | No reservation
Hours: Saturday, September 19, 2026 — 8:00 PM to 9:00 PM, 9:00 PM to 11:59 PM | Sunday, September 20, 2026 — 8:00 PM to 9:00 PM, 9:00 PM to 11:59 PM
Heritage Days 2026, the Renefer Route
Renefer Route
Gabrielle Thierry, painter and biographer of Renefer, invites you to discover his art by walking through the panels mounted high above the city, at the Musée de la Batellerie square, then along the Seine to the end of l’Oise.
Raymond Renefer was a renowned painter, illustrator and engraver, beloved by connoisseurs. His distinctive style and commitment to art and culture make him a key figure of the 20th century, and he played a pivotal role in elevating the artistic profile of the Seine and Oise confluence.
Participation requirements: Free | Booking required - culture@mairie-conflans.fr
Schedule: Saturday, September 19, 2026 — 10:00 a.m. to 11:30 a.m.
Heritage Days 2026: a workshop exploring the water cycle
Workshop on the Water Cycle
With the duo of artists Anne Cleary and Denis Connolly on hand, the Dans le Sens de Barge collective runs two workshops exploring the water cycle, rooted in observations of the landscape and the Seine. Some of the artists’ proposals from the exhibition Amers Remarquables that touch on the theme will also be showcased. The children will then be invited to tell the landscape from their own vantage point and describe it as a collective artwork, aimed at raising awareness of the issues and challenges surrounding water.
Participation terms: Maximum 30 children per time slot - Free | Booking required - culture@mairie-conflans.fr
Times: Saturday, September 19, 2026 — 2:30 PM ⤏ 3:15 PM, 3:30 PM ⤏ 4:15 PM, 4:30 PM ⤏ 5:15 PM
Heritage Days 2026 at the Orangery of Prieuré Park
Exhibition "Paradisi in Sole Paradisus Terrestris" at the Orangery
As a student at the École des Beaux-Arts in Paris, Félix Crossonneau develops a painting practice that traverses two seemingly opposed worlds. On one side, large, gestural, expressive abstract canvases; on the other, small, figurative works—minute, intimate in scale. These two languages sometimes converge within a single piece thanks to an inlay technique that lets abstraction and figuration converse.
The exhibition runs until October 11, open Wednesdays, Saturdays, and Sundays from 1:30 to 5:30 pm.
Participation requirements: Free admission | No reservation required
Schedule: Saturday, September 19, 2026, 10:00 a.m. to 7:00 p.m. | Sunday, September 20, 2026, 10:00 a.m. to 7:00 p.m.
Cyanotype workshop at the Orangerie
After a plant harvest in the park, participants will assemble their own Orangerie window, pairing plants, drawings, and acrylic markers. The creations will then be printed onto fabric using the cyanotype process. Together, they will form a large collective frieze.
Participation conditions : Free admission - Free of charge | No reservation required
Schedule: Saturday, September 19, 2026 — 2:00 PM to 5:00 PM
Heritage Days 2026 at the Blaise Cendrars Media Library
Aucun événement annoncé à ce jour, le programme est mis à jour en fonction des annonces officielles.
Heritage Days 2026 at the Port Saint-Nicolas Halt
Guided tour of the tug Triton 25
The last tugboat built in France, in 1954, later converted into a pusher in 1960, this heritage vessel is listed as a Historic Monument. A tour reveals the captain’s quarters and his mate’s cabin, the engine room, and the wheelhouse. Two other heritage boats are moored at the heritage stop: a pontoon-barge serving as a staging area for tours of the Triton 25, and a steam-powered tug, the Jacques, dating from 1905, also listed as a Historic Monument.
Participation requirements: Free | No reservation required
Hours: Saturday, September 19, 2026 — 10:30–12:00, 14:00–18:00 | Sunday, September 20, 2026 — 10:30–12:00, 14:00–18:00
Tour itineraries
Aucun événement annoncé à ce jour, le programme est mis à jour en fonction des annonces officielles.
Ready to set sail for Conflans-Sainte-Honorine?
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Dates and Opening Time
From September 19, 2026 to September 20, 2026
Location
Conflans-Sainte-Honorine
conflans sainte
78700 Conflans Sainte Honorine
Route planner
Accessibility info
Prices
Free
