La Gaz'Run is a community running event in Gazeran, a village in the Yvelines department southwest of Paris, with races typically held at the end of March. Organized by USEP de Gazeran, it raises funds for cultural and sports projects at the village's preschool and elementary school. The program is designed for families, not for competitive timing: races are untimed, with options from short children's runs of 1 km and 3 km to longer distances like 12 km, 21 km, and a walking route.
The event utilizes the forest of Rambouillet and the village, offering participants a choice between trail running, road sections, walking, and an orienteering format. The orienteering race is available for individuals or teams of up to five, where participants seek nine markers while exploring Gazeran. A separate Gaz'Run Challenge features a 3 km loop with approximately 30 m of elevation gain, allowing runners 30 minutes per lap to complete as many as possible throughout the day. All participants receive a post-race refreshment, aligning with the event's distinctive, spirited, school-fundraiser atmosphere.