To reach the starting point, leave Saint-Étienne via the south-west, pass through La Ricamarie, then head towards Saint-Genest Malifaux. After a few hairpin bends, you will see the dam below on the right. There is a small space at the side of the road where you can park two cars, in a right-hand bend, just at the starting point of the walk.
(S/E) Take the small road down to the dam to the "guard" house (road closed to cars, except for residents).
(1) Cross the dam and turn left. Then walk along the entire length of the reservoir to the first small river that feeds into the lake.
(2) Cross the river and climb up the opposite bank (steep climb for about ten metres), then follow the path to the left.
Cross two more small rivers to reach the other side of the lake, which is sunnier (south/south-west facing).
At the dam, take the arrival road on the right back to the car park (S/E).