As above, tubes, spare tyre, break pads. Duct tape, I like to tape up bits of the bike to keep wear down a bit – eg frame for rock strikes and wear/tear from the ski lifts.
Spare short liners, gloves, socks and/or washing powder. Wearing the same kit every day for a week gets a bit spicey and even if you wash stuff it might not dry overnight. Plenty of ibuprofen, vasceline, sudocrem – everything gets sore !
By the way if you haven’t got them yet warning triangle, yellow safety vest, breatherliser (these are reelly cheap in French supermarkets so buy locally)
I am a map geek so go on geoportal.gouv.fr and check out the area on IGN mapping (you can print a few) and/or buy a map when you are out there. They are great for searching out trails away from the marked stuff.