The village of Gourdon comes up in the prologue to the novel. So that you can visualize better what's being discussed, as well as visualize the area, I am attaching two pictures of the village of Gourdon.
Gourdon is a beautiful little village, perched on top of a promontory in the middle of the Pre-Maritime Alps. As you travel the road toward it, you don't know it's there until you come out of the forest and, bam, there it is. The first picture shows you how it looks as you turn out of the forested road.
The second picture is an eagle's eye view of the village where the hiking trail going down the mountain is shown.
If you are ever visiting the area, you really need to go there.