if you're simply cycling to Paris it is perfectly possible to find your way by using Google Maps and printing bits out. You have to hit the 'walk' button, and check the junctions to make sure the map isn't directing you across a field, but, while it takes a bit of time, you will be able to work out where you can stop for a bite to eat.
If you do buy maps, the IGN series is a better bet than Michelin, and costs about seven quid a map from Stanfords.
I'd buy a map of Paris and bigger than 1 to 100,000.
If you're going via Dieppe I can send you a link to The Fridays route
I'd like to check out this route please - mebee can link up with it from Calais. thansk