@ACRe19 GR91 seems to fit that bill quite well - start from Grenoble (train from Paris, bus or hike up to Saint Niziers), 4 or 5 days of easy hike in a nature reserve down to Die (no, mr Bond…) or Crest, return to Paris by night train. Camp or sleep in mountain huts.
Maybe on the shorter side depending on your pace, throw in an ascent of the Grand Veymont if you’re making good time :-)
@ACRe19 GR91 seems to fit that bill quite well - start from Grenoble (train from Paris, bus or hike up to Saint Niziers), 4 or 5 days of easy hike in a nature reserve down to Die (no, mr Bond…) or Crest, return to Paris by night train. Camp or sleep in mountain huts.
Maybe on the shorter side depending on your pace, throw in an ascent of the Grand Veymont if you’re making good time :-)
edit: here are a couple of pics I took three years ago: https://www.lfgss.com/comments/16089189/