bjorgts wrote:Has anyone walked from Cluny to Le Puy? Do they follow a GR-route then?

This may encourage you. In 2006 I went by bicycle from Canterbury to Santiago, stopping to meet a group from England in Taize for a week, then I continued from Cluny to pick up the Chemin from Le Puy. Although I used the tarmac from Cluny to Le Puy on that occasion, I crossed the footpath many times and it is clearly marked all the way as a Chemin St Jacques as well as the usual red and white GR markers. By a church door - I think it was in Sainte Cecile, on the D19 about fifteen km south of Cluny, I saw a noticeboard for walkers on the Chemin St Jacques. It showed the route clearly and gave me the impression that it was well established, so you should have no difficulty. As I said, I used the tarmac but I saw continuous evidence of way-marking as the chemin crossed the road at different points. I hope this helps.
Bon chemin!
Gareth