This hike starts at the car park after "La Charmette" when coming from Manigod. This car park is at the end of the road and at the start of a track used to climb up to the alpine farms.
(S/E) Take this track, which first climbs through the forest and then emerges to cross the mountain pastures.
(1) You will reach a small stream, the Fer, which you will need to ford. Continue with the stream on your right and move away from it before reaching another ford.
(2) Follow the Ruisseau Le Fer stream again, then cross it and turn north-east, then east to reach the Aulp de Fier d'en haut mountain farm.
(3) The trail climbs behind the farm and turns south, taking you to the Lac du Mont Charvin via some rocks and a small slab.
(4) Go around the lake, keeping it on your left, and climb up to the pass at 2,085 metres.
(5) Then, still skirting the lake, return to the path you took on the way up.
(4) Take the same route back to the car park (S/E).