Day 9 Trient to Tre le Champ
From Le Peuty take the track away from the campsite. This turns into a path which winds steeply up through woods giving good views back down the valley, on leaving the woods the path becomes more gentle and the Refuge du Col de Balme comes into view set perfectly in the centre of the Col de Balme (2191m).
Upon reaching the col you once more have a view of the chamonix valley and across the border from Switzerland back into France. The route turns right through the ski resort to the Col des Possettes (1997m) and up to the Aiguillette des Posettes (2201m). It then follows the ridge line to the long descent down to Tre LeChamp.
There is not much accommodation so head down to Argentiere where there are various hotels a large supermarket and restaurants. The is a campsite just south of the town, although a better option which is less of a detour is the camp site at Les Frasserands.
Day 9 Varient Trient to Tre le Champ
This is not the most scenic route but if you are feeling tired it is an easier option. The variant is as per the normal route to the Col de Balme (2191m) where you take the route straight down through the ski slopes to Le Tour where you follow the road down to Montroc before heading up to Tre le Champ.