On a boulder along the blue path, 700m from the bivouac in direction of La Mare aux Fées. Start with your feet on the good ledge and go up directly or a bit to the left.
From the Bourron Marlotte bivouac follow the road directly into the woods towards Route de la Grande Vallée. Then, follow the blue trail to the right, just before the crossing with Route des Barnolets. Follow the blue trail for a little further than 100m. The problem is just a little past Allez, Péken, not far from Sashimi.