Start: Go to Chamonix - Les Praz. Park in the Flégère lift car park.
Take the gondola lift, then the Index chairlift. In 30 minutes you go from 1000 m to 2400 m.
(S) When you get off the chairlift, turn right, then, opposite, join the path running North-East towards Lac Blanc (signposted). Head towards the former Index station (signposted), where you descend. There's no risk of getting lost.
(1) Round a rocky bar (the Tête d'Aubuy) to the right. No particular problem (although children should be supervised).
Continue North-North-East to Lac Blanc (lake).
For the return journey, walk down to La Flégère. There are two ways of doing this. As far as we're concerned, we advise you to take the slightly longer route, which passes close to the Chéserys lakes (indicated on the route). It poses no problems in terms of navigation.
(2) Leave Lac Blanc by taking the path below the refuge: signs "Lacs de Chezerys" then "sentier pédestre".
(3) After the refuge, heading East, it's very steep and chaotic at first. The path is marked with wooden bars set into the rock. Head towards the Chéserys lakes. There is a passage with two ladders (probably one going down and the other going up...).
(4) After the first lakes, you come to a crossroads. Turn right (there's a sign for "La Flégère").
(5) You come to the TMB (Tour du Mont Blanc), a GR® trail marked in red and white. Head South (right).
It takes you back along a comfortable, signposted path to La Flégère where you can take the gondola back to the car park. (E)