Sentier Denecourt-Colinet (Blue Trail)

The Sentier Denecourt-Colinet Blue Trail is an 18 km one-way route traversing the heart of the Fontainebleau Forest between Fontainebleau town and Barbizon, in the Seine-et-Marne department of Île-de-France. The trail was created in the mid-19th century by Sylvain Denecourt, a retired soldier who spent decades hand-carving paths and viewpoints through the forest, and later extended by Charles Colinet. The blue-blazed network he established remains one of the most historically significant recreational routes in the Paris Basin. The western trailhead is at the Château de Fontainebleau car park in Fontainebleau town, reached by Transilien train from Gare de Lyon to Fontainebleau-Avon (around 40 minutes, approximately €8.70) followed by a 10-minute walk to the forest edge. The route finishes in Barbizon village, from where Bus Ligne R returns to Fontainebleau-Avon station; bus frequency is limited on Sundays. No permit is required. The full trail covers 18 km one-way with 180 m of cumulative ascent and takes 5 to 7 hours. The surface alternates between broad sandy firebreaks, narrow sinuous paths through heather and gorse, and sections across open sandstone plateaus with wide views. Continuous pale blue paint blazes on trees and rocks mark the route throughout; wooden signposts at major junctions confirm direction. Key landmarks include the Rochers de la Reine sandstone crests with views over the Château de Fontainebleau park, the Gorges d'Apremont sector midway along the route, the Plaine de Barbizon heathland, and the arrival into Barbizon past the historic Auberge Ganne — now the Musée des Peintres de Barbizon. No drinking water sources exist along the entire route and there are no staffed facilities; all food and water must be carried from the start. Walkers seeking a shorter outing can walk the first 8 km from Fontainebleau to the Gorges d'Apremont viewpoints and return to Barbizon on a direct connecting path, reducing the total to around 12 km.