Halloween 2025 in Osny (95): pumpkin contest and immersive trail at Château de Grouchy

Have you heard? No, you're not dreaming! It'sHalloween 's chilling breath that's coming back to haunt Paris and the Ile-de-France region... And it's not sparing the Val-d'Oise (95)! On Friday, October 31, 2025, the Château de Grouchy, a splendid 18th-century residence nestling in 42 hectares of parkland in Osny, will be transformed into a theater of horror, where mystery, thrills and fantasy will be the order of the day.

Starting at 2pm, the festivities kick off with a pumpkin contest for young and old alike. At 2:30 and 3:30 pm, it's time for some (relative) sweetness, with children's storytelling to give you a gentle chill before night falls.

When the park goes dark, the castle reveals its most disturbing side... At 8pm, the most daring will enter the dreaded "Grouchy Haunted", an immersive haunted trail (ages 8 and up) that stretches over two floors of the manor house. A journey between shadows and whispers, where every step promises an adrenaline rush... and a few nervous laughs.
At 10:30pm, after this horrific journey, warm your icy bones with steaming pumpkin soup, served to soothe spirits... and hungry stomachs.

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And because Halloween is also about the art of the look, a photo contest for the best disguise will crown the evening's most stylish creatures.

The event is open to all brave souls upon reservation. So put on your spookiest costumes and come experience a spellbinding Halloween night in the historic setting of Château de Grouchy.