Prolongation of the traverse of Coup de Canon (red n°15). Start at the right angle, traverse a first face, continue on slopers after the exit of Coup de Canon (red n°15), downclimb at the left angle, low traverse in the second face and exit after the next angle.
NB: it's also possible to exit with a mantle at the level of the big holds just before the last arete (same grade, first known ascent by Christian Mérimèche).