25 minutes from Bordeaux, on the Garonne heights at the tip of Entre-deux-Mers, Château Formont is set for a busy summer. Two events follow a few weeks apart in its 4-hectare park: a big prestige and vintage vehicle gathering on Sunday June 14, then the 4th Osmose Festival on July 11-12. The first serves as an elegant, family aperitif, the second follows with two days of electronic music in the park's heart.
June 14: prestige and vintage vehicle gathering
Sunday June 14, from 10 am to 6 pm, Château Formont hosts a gathering for collection car and exceptional vehicle fans. Free entry. Mustang, McLaren, Porsche: the château courtyard and park turn into an open-air exhibition, mixing 60s-70s icons and contemporary supercars. On the program: exhibitor villages, artists, catering and relaxation area, without forgetting the screen broadcast of the 24 Hours of Le Mans, running that weekend. The event is organized with the French Federation of Vintage Vehicles, Esprit 4 Roues and Road-Trip Aquitaine.
It's a quiet event, ideal for a family outing or among fine mechanics enthusiasts, in an uncommon heritage setting. Also a good chance to discover the estate before it changes face in July.
July 11 and 12: Osmose Festival celebrates its 4th edition
A month later, the same venue shifts to a completely different energy. Born in 2022 in the wake of the château's purchase by Olivier and Laurent Prévot, Osmose Festival has become in a few years one of Gironde's most identified electro meets. The 2025 edition gathered nearly 5,000 festivalgoers over two days, with headliners like Joris Voorn, Upsilone or Victor Ruiz. For 2026, Olivier Prévot and Anaïs Brugues's team announces 2,500 festivalgoers expected daily, 25 artists, 3 stages and 170 people mobilized in the organization.
Three stages structure the festival. The Forest Stage, nestled in the tree park, becomes this year the festival's main stage: a broad lineup, from house to melodic through techno, carried by a spatialized sound setup inspired by the Boiler Room concept. The Pool Stage, with château view, will offer a quieter pool party to sip a drink with feet in the water. The Indoor After, in the big reception hall with exposed stones, takes over at night, programmed directly by the festival team.
Lineup-wise, Saturday July 11 has as headliners Petit Biscuit, Marina Trench, Kitsch & Sash and Traf, plus Elmyx, Karl Line, Mac Milio, Medusyne, R.A.F.A, Ten Blues and XKA. Sunday 12 takes the form of a pool party hosted by Biome x La Maskarade and by Bordeaux collective La Molécule. Also note: giant-screen broadcast of a World Cup match Saturday and Tour de France Sunday, plus a mechanical bull, a Slip'N Slide, and several food trucks (with vegetarian, vegan and world cuisine options) set up this year in the chill zone, as in the previous edition, to give festivalgoers a more airy space.
Practical info
Location: Château Formont, 4 rue de Formont, 33440 Ambarès-et-Lagrave. Built in 1723, listed 18th-century historic monument, being transformed since 2022 into an event platform (15 events planned in 2026, 10,000 people expected).
Access: 25 min by car from Saint-Jean station (A10, exit 43 « Sainte-Eulalie »), 3 min from La Gorp station, or by public transport via tram A (« La Gardette » stop) or tram C (« Place Ravezies » stop), then bus 7 to Beloc stop. Free parking 100 meters from the site, shuttles planned during the festival after, carpooling possible via Togetzer. The château is also served by bike path.
Osmose Festival, hours: Saturday 3 pm to midnight, after from midnight to 6 am; Sunday 2 pm to 8 pm (any exit is final from 8 pm).
Osmose Festival, prices: €28 Saturday, €7 Sunday, €15 the after, €120 VIP pass. Cashless payment on site (bracelet rechargeable by card or cash), with €5 offered per €50 tier recharged in advance. Unused credits refundable on simple request.
Useful links: osmose-festival.com and @osmosefest on socials. Festivalgoer contact: hello@osmose-festival.com.
