On the boulder to the opposite of the end of the tunnel on the blue path, just after the boulder marked "D", en 20-30m above Haute Précision. Low sistart with the two hands in the round crack, climb the roof with a far dynamic move and exit with the arete right hand without touching the small boulders around.
Update: the end of the ledge of the dyno has broken off in 2023 and the stone has become fragile.