Good luck finishing that on a tourist visa! Plus, camping is prohibited in France, so you'll need to walk to a town to crash every night. Huh!
Camping appears to be allowed along most of it according to the website.
Only once a woman asked me what I was doing in her field, I asked politely if I could stay the night, she said one night is OK and that was it. The only reason I had this encounter is because I was so tired that I didn't bother to look for a hidden place. I just built my tent in the middle of her flat field.