I think somewhere around here the original way of St James turns right on a path and is well signed from there on.
The GR65 was changed 20 years ago to pass some Gites and restaurants.
There must be a (commercial) reason for signs in several languages at signposts to NOT follow any other way even if you are told so but only the GR65.
Image and track I will upload in not too close future.

coming from north until about here GR76, Chemin de Compostelle and d'Asssise follow the same route. GR76 then turns right.

regarding the markings on the road the way of st James goes this way to the bridge

This is an isolated dwelling - there should be a landuse=residential around, not just farmland.

On the ground in the very center of the tower is a triangulation point. Since I don't know if the mapped tower or the mapped triangulation point are more exact I just write this note for people which know the whereabouts better.

here is a path with steps (see uploaded log)

Around here - the first driveway to the west on this part of D94 - is an organic farm with a shop open from 16:30 on vendredi.

Check if this highway exists and if yes: how it crosses the railway. Bing Imagery doesn't show much helpful things.