In reply to calum404:
In that case you can find cooler, north-facing venues, but it'll still be very hot. Have been here in Oct, Nov and even Jan and it's often still very warm, but it might be doable for you in Sept.
The best 'local' venue at altitude I've been to is Gréolieres, (not in the Rockfax guide) which has some easier stuff and should be a bit cooler. But it's still south facing and not the easiest of places to reach by PT.
La Colle Sur Loup can be shady and is reachable as is St Jeannet, but both can be very polished, particularly on the easier routes. Think there is some dws near Antibes - Coco beach or something like that - but have never tried it so can't comment. You might try posting on the camp2camp forum for some decent local knowledge.