To get to the starting point from Modane, go to Valfréjus station, cross it and then follow the signs for the hamlet of Le Seuil. Pass through the hamlet and continue on the road that climbs to the railway tunnel chimney. Pass the path that leads back to Le Mélezet on your left and stop at the start of the next path, also on the left. There is a recess where you can park.
(S/E) Walk along the carriage road that climbs uphill.
(1) At the fork, take the path that climbs to the right into the wooded area for about 150 metres.
(2) Take the path on the right to leave the wooded area and reach the ruins of Le Pontet.
(3) Climb through the ruins, following the most obvious path, which gradually becomes a well-defined trail. Climb up the switchbacks until you reach a fork.
(4) Take the path on the right. Be careful to note its location so you don't miss it on the way back. You will reach an alpine shelter at La Combaz.
(5) Continue in the same direction, generally speaking, through the pastures, which have obscured the trail for a few dozen metres. Cross a small stream and then join a larger one.
(6) The path reappears to mark the crossing point of the stream. Cross the stream and continue the ascent, making a wide curve to the left to reach the top of the ridge located directly above the stream you have just crossed, which is easily identifiable in the landscape. The path becomes a little exposed, without being difficult, to reach a first plateau.
(7) Continue climbing, following the course of the stream.
(8) Follow the trail, which is marked again, and cross an area of scree, following the contour line. Then descend a little to discover the Grand Vallon, the end point of our route.
(9) After enjoying the view, turn around and retrace your steps, paying particular attention to the fork in the path you noticed on the way up.
(4) Turn left downhill to return to the starting point (S/E).