We love this car rental service and recommend them whole-heartedly: Truche Location. I met a man on a plane whol told me about how to avoid all the hassle of schlepping over to the car rental depot, queueing for hours, filling out forms etc, etc. Not the best way to start your holidays.
You call Truche up (+33 (0) 93 63 95 66 they speak English: don't forget to mention Go Provence sent you to get the best possible service) and they send a friendly someone to meet you in arrivals at Nice (with your name on a placard), help you with your bags and walk you to the car that's waiting for you. Best news is, when you leave, just leave the car in the parking lot, put the key in an envelope they provide and lob it in the post. Brilliant!
Strange why they should call themselves "trout".