Park your car as to Bas Cuvier.
The total approach is between 700 - 1000m, depending where you want to go.
Start walking the Route Mory de Neuflieux. Either go left at 400m, walk to Duroxmanie and follow the blue path until you get to the area.
Or you can walk along the Rte Mory de Neuflieux (for 700m) until you take a left and walk straight up to big four (100m).
After that it's pretty easy. You'll find paths going around the sector. Access to North side of Rempart is from the north west side of L'Angle Allain. On the east you'll find many access points (via Respire and north east from there) until you find the next path going west-east.