Park in the Col de Belle Barbe car park.
(S/E) Take the GR track above the Vallon du Grenouillet until the Ford.
(1) Continue ahead, climbing the Ravin du Mal Infernet until the Lac de l’Écureuil: It is a lake but has been empty for years.
(2)
Walk along it on this track, ignoring the next two trails to your right that go around the lake. Continue in the direction of points 139 and then 212 opposite the Sommet des Redonnets higher up, and reach the Croupe Baptiston.
(3) Continue fully west past a small lake on your right. Go back to the Baisse de la Grosse Vache.
(4) Take the GR opposite in the direction of point 180. Then go down to the right toward the next Ford, (picnic possible along the stream).
(5) Climb the track to reach the Ruisseau de Maraval stream.
(6) Continue straight along the stream up to the Pont des Cantines bridge, where's there's a confluence of streams.
(7)Cross the bridge and take the track along the Ruisseau (stream) du Perthus, whereby you'll enter the Perthus Ravine, without any difficulty, continuing until the Pont du Perthus.
(9)Turn left to go back to the Col du Mistral.
Be careful not to take the track on the left but one that descends back to your departure point at the Col de Belle Barbe (S/E).