Park at Hameau de la Jars, in the municipality of Quaix-en-Chartreuse.
(S/E) At a large bend in the road, near a cistern, a yellow-marked path heads west. Follow it to a three-way junction.
(1) At the three-way junction, continue straight ahead (and do not follow the Trépalou path, marked in yellow, which enters private property, see practical information) and follow the Bois Bonzier forest road.
(2) Take the leftmost path, which climbs relatively steeply to reach the Col du Bois Ronzier.
(3) Take the ridge path on the left, marked in yellow. Shortly before the Aiguille de Quaix, the path splits in two.
(4) Continue straight ahead to reach the Aiguille de Quaix. The peak can be climbed, and a rope helps to get over the top, but the climb is not easy (especially the second pitch) and should be avoided if you have poor footwear or are unsure of your abilities (once you're at the top, you have to be able to get back down!!!). For those who do not want to climb, admire the view from the bottom of the needle, the view is well worth it. Then turn back to reach the crossroads.
(4) This time, take the path on the left to reach a wide forest path.
(5) Take it to the right and follow the marked route. The path descends for a long time and then splits into three.
(6) Take the leftmost path and climb back up to the crossroads where the circular began.
(1) Follow the route in reverse to return to the car park (S/E).