Start: Access via the Col des Montets road, reached from Chamonix or Martigny via Switzerland. Park at the Tré-le-Champ parking lot (point 1416 on the IGN map); if saturated, try a higher, triangular parking lot at point 1429 or the Col parking lot at point 1461.
(S/E) From the bottom of the car park, cross the stream to take the well-marked GR® path (direction Lac Blanc indicated at each junction), which rises in the forest to the south and then to the South-West. It rises steadily, crossing the path leading up from Argentière and reaching the distinctive Aiguillette d'Argentière.
Pass the Aiguillette on the right: the route then takes in two spaced, more delicate passages, equipped with ladders and metal ramps. The rest of the route is sometimes equipped with steps attached to the rock, making it easier to climb. Reach the Tête aux Vents ridge and climb straight up on the right to reach the junction with the Grand Balcon Sud coming from La Flégère.
(1) Climb towards Lac Blanc, whose refuge is now visible, over a rocky hump to reach the crossroads serving Lacs des Chéserys.
(2) Continue left, reaching Lac Supérieur de Chéserys (2210m). Go around it to the right to admire the scenery and climb the marked path, sometimes equipped with steps and passing a double ladder (without difficulty) to the Refuge du Lac Blanc.
(3) Stay at the foot of the refuge to skirt the first lake to the right.
(4) From its shore, immediately take a path that rises to the North, marked with large yellow dots. This path rises steadily, skirting the relief, then gradually levels out to reach a hump of soft rock overlooking the main Lac de la Persévérance, in its mineral setting at the foot of the Aiguilles Rouges. Descend to the edge of the lake, choosing a convenient passage through the rocks and scree.
(5) Return to the arrival hump and pick up the access path: after a hundred metres or so, the ridge immediately to the west comes into view: climb it without difficulty via one of the passages between the rocky outcrops. There is no path, but a few tracks and cairns. Reach the ridge and its high point, called Tête sur les Lacs on the maps.
(6) From this summit, spot a small plateau and a wide talweg running towards the upstream Lac Blanc valley. Descend here, using the cairns to mark possible passages. At the edge of the valley, on a lateral moraine, paths lead downhill (south). After bumps offering views of the lake, cross the torrent coming from the Aiguille du Belvédère to find a true path that skirts the main lake on the right, at the cost of a few ascents on the flanks. Descend to water level to pass from one lake to the next and return to the refuge junction.
Note: if you're apprehensive about the off-trail route back to the top of Lac Blanc (or in case of fog), you can take the ascent path back down to the Refuge du Lac Blanc.
(3) Take the path used on the way up in the opposite direction, pass the ladders and end up at Lac supérieur de Chéserys, which you skirt to the right. Rejoin the crossroads at the hump you passed earlier.
(7) Quickly take the left-hand path down the grassy slopes to the two Lacs de Chéresys at sight. Aim for the strip of land between these first two lower lakes, on which a clear path emerges, follow it and keep level with it.
You will soon see a 3rd lake in which the Aiguilles Rouges are reflected. Turn right to aim for the level exit of the plateau you have crossed. Discover a final lake (dried up at the end of the season), which the path (now almost a footpath) skirts to the right, before continuing due east until you reach the Grand Balcon Sud.
_ Note : if you don't want to take this passage off the real path visiting the 4 lower lakes, you can stay on the path you took on the way up and, at the first crossroads, turn left to follow the level path to the Col des Montets, which leads to the Grand Balcon Sud crossroads.
(8) Turn left at this important junction to follow the Grand Balcon Sud (GRP® Tour du Pays du Mont Blanc), which runs North-Eastwards across a narrow but long plateau, losing little altitude (and even a few slight ascents). Reach the Remuaz sector.
(9) Here, there's a break in the slope: the path now descends the slopes overlooking the Col des Montets, first in a traverse, then in tight switchbacks. The trail remains well marked and easy, but this area is hard on the knees. As you approach the Col des Montets, which has been clearly visible for some time, join a new junction.
(10) Leave the Col des Montets path to the left and go straight down to the right towards Tré-le-Champ, where the path joins a shallower track descending to the right, which in turn leads to the road at the 2nd car park. Cross the road to take a path that runs parallel to it and leads back to Trè-le-Champ (S/E).