Brevet des Chateaux is a cyclotourist bike ride based in Bonnières-sur-Seine, France, where riders gather at the communal hall. It is a one-day June event, following the French brevet style: a measured long ride, not a closed-road mass race.
The main route covers 115 km with approximately 1,000 m of climbing, providing a steady day without becoming an extreme mountain challenge. Bonnières Cyclo organizes the ride, which is listed in the Brevets / 100 Km / Fédéral category. The name suggests a château-themed route. The event was in its early editions, with the second and third editions held in consecutive years.