Cross it, and climb the other side of the valley to the start of the climb. If you want to do both climbs, start with the Brousse. At this point the icefall is enclosed in a claustrofobically narrow chasm of the face. The final wall is the most imposing and harder section as well. Climb on the right and grab a succession of narrows walls.
Much easier ground leads to the end of the climb.
Traverse on easy ground to the right pointing to two very prominent trees placed about 100 meters over the exit of the Rochemolles fall. At this point you'll wish you had studied better the landscape while you were standing down there in the road. From the trees descend the gorge originating the Rochemolles fall looking for the very last tree before of the BIG drop. Next stop is belay two. Time to start the second climb of the day.