The only thing that I can suggest would be to contact the Fédération Français de la Randonnée Pédestre better known as the FFRP -- from my book on hiking in the Luberon, I have an address as 14, rue Riquet, 75019, Paris. They may have a website, but perhaps this is a start for your friends. I would go on websites for Provence itself or onto hiking websites and try there. Sorry I wasn't much help, but this FFRP puts out great books, so perhaps they can help.

Also, the headquarters of the Parc Natural Regional du Luberon is located in Apt. They were very helpful when we were there and there is sometimes a person who speaks English... Their phone is: 04 90 04 42 00 -- Again, I would have your friends see if there might be a website.

I hope this will be a start.

Good luck! Susie Newton, MA