Start from the car park at the Essarts-le-Roy cemetery.
(S/E) Head east and walk along the cemetery on your right.
(1) At the fork, take Chemin de Vaujoyeuse on the left. After about 500 metres, this small tarmac road continues as a dirt track. Leave the path leading to Ferme de Vaujouyeuse on your left. At a fork, keep left.
(2) At the next intersection, turn left. Follow a path between two fences (wet passages) and reach the source of the Yvette, marked by a small statue.
(3) Turn around and return to the previous intersection.
(2) Continue straight ahead. Cross a small bridge over a stream and climb up the other side.
(4) At the top of the hill, turn left (east). The path soon gives way to a street (Chemin de la Butte Rouge) which crosses the village of Les Layes.
(5) At the crossroads (chapel on the right), turn left onto Chemin de l'Yvette. This street continues as a dirt track that descends through the Bois des Layes.
(6) At the bottom of the valley, turn right and cross the Yvette. Then cross the Route de l'Yvette and continue along the Route des Layes. Take thefirst right, Rue du Prieuré.
(7) At the old priory, take a fairly steep path on the left. At the top, follow the wide Chemin de la Porte Dorée on the right. Continue straight ahead for about 1.5 km. Walk along the left-hand side of the Château de la Boissière Beauchamp park until you reach a crossroads.
(8) Take a small path on the right. Very quickly, this path descends a very steep slope (there are steps). At the bottom, you will come to a road. First turn right then left to take a path that leads to Moulin Neuf.
(9) Cross the two branches of the Yvette and climb up the hillside. At a fork, turn right and continue climbing. After about 750 m, you will reach an intersection (small pond).
(10) Turn right, leaving the pond on your left, and you will soon reach a rocky outcrop. Turn back to return to the previous intersection.
(10) Continue along the main path to the south-west. Join a road (Chemin des Beaudoins) and follow it to the right. Cross the hamlet of Les Beaudoins and continue along the road. At the end (chapel opposite), turn right and you will immediately come to a crossroads that you took on the way there.
(5) Turn left and pass the last houses in the hamlet.
(4) At the intersection on a downhill slope, take the path on the left. At the next intersection, go straight ahead and cross a stream. Continue straight ahead and pass under a power line. You will rejoin the tarmac road at La Sartelle.
(1) Continue straight ahead to the cemetery car park (S/E).