Other than avoid Paris like the plague - which we're planning on doing!
Will have DS1 (8), 2 (5) and 3 (1 and blooming grizzly with it at the moment) in the car - am planning on lots of snacks, water, dvds, toys and books for the kids. We have the French car supplies/breathalyser etc we require. We have one of those auto pay fobs for the toll roads.
Anything else we need to survive the journey with our sanity relatively intact?