Stunning views in the surroundings of the foothills of mont Blanc...
On the plateau of Bellevue, pass behind the restaurant La Chalette and continue on the dirt road on the right leading steeply up to the ridge of Mont Lachat, then up to the summit, near the orientation table.
To go back down take to the right of the orientation table and to join the path along the rails.
At the intersection, take the down going path on the left, not following the railway. Follow this path on the slope of Mont Lachat, until you reach the starting point at Bellevue.
Easy