Let's go to the Périmètre shed to enjoy an amazingview over the Roizonne Valley. Please keep in mind to stay on the trail as you are in a very rich but fragile area. Nature deserves to be protected.
Go to the Alpe du Grand Serre waterfall. From here, take right, a large trail going up in the forest. After 2 hairpins - around 20 meters - you reach the combe of La Blache (danger sign), then go straight, leaving apart the left side trail. After 10-minute walk, you reach the state forest (sign), keep on straight, leaving apart the right-side trail getting down. After half an hour, please be careful: le trail keeps on going on the left side in the forest just before a combe. Go up peacefully under trees, the trail makes several switchbacks and reach a big clear combe (open your eyes as chamois and deers are often there). Then th etrail goes back in the forest. You're not far, watch the right-side junction, here is the Périmètre shed. You arrive there from above, and enjoy an amazing view over the whole Roizonne valley, Armet range, Tabor and skiing slopes. Same way back, or you can also take the left trail getting down from the shed to the east-entrance of Alpe du Grand Serre, near La Blache war memorial.