I went with 2 friends in 2008.
We got the ferry from Dover to Calais, then rode down the west side of France, stopping in cities like Caen, Rouen, Le Mans, Tours, Limoges then down to Montpellier.
When driving through northern france you should expect just long straight flat roads. I was expecting something good, but it was so dull. By the time we got 2 days in and were only as far as Tours, we decided to ditch the back roads and go on the tolls to get to the south coast more quickly. We wasted so much time riding on the back roads trying to find something twisty, the tolls are a better option to get to the south quickly, but even at best, i reckon it would take 2 days on a bike. With all the fuel stops and stuff, you just dont get as far as you would in a car.
The only exception to this was the massif central around Clermont Ferrand area. There are some awesome roads there. Wide, twisty and massive straights to get up to full speed. Just look at the area on google maps and you will see the number of twisty roads.
Without a doubt though, when I go again, ill get the ferry to Bilbao in Spain and avoid Northern France like the plague. It was so dull, and I did it on an R1 so after 3/4 days of that, my wrists were just about shot.
When you get to Monpellier everything changes, really. We stopped for a piss as we came down the mountain after the Milau viaduct, and it was like someone had flicked a switch. It had gone from being cold and damp, to cactus at the side of the road and 30 degree heat
But the roads, really I have never seen anything like it. The coast road from Monpellier to Marseille is good, but once you get past Toulon (staying on the coastline) you will not believe how good that road is.
It is twice as wide as our roads over here, perfectly smooth and just hairpin, after hairpin, after hairpin. The road winds up and down the cliffs hanging over the sea about 100m below you and has fairly long stretches between villages of 5-15 miles where you can really hammer it. I swear to god I have never been so happy as when I was riding along that road.
Anyway the road carries on past Saint Tropez and Saint Rapheal onto its best bit between Saint Rapheal and Cannes. We stopped at Cannes and had something to eat on the beach and looked at all the millionaire's yachts.
We stayed in Cannes that night ready for the road we had come to France for...the route Napoleon
It was quite hard to find the start of it, but basically it goes from Cannes to Grenoble and is just over 200 miles of THE best biking road you will ever likely see. You head out of Cannes toward Grasse, it isn't signposted very well, but once you get to Grasse you follow the D4 on toward Digne. It's hard to explain just how good this bit of road is to be honest, but there is nothing even close in this country. It is right through the middle of the Alps, so it's very high, your bike will lose power for a start. My R1 wouldn't pull power wheelies even in first gear for most of the trip, that's how high you are. As you can imagine, there arent many people living in the middle of the alps, so whereas over here you ride for 3 miles and then hit a 30, then go through a village, over there you get 20-30 mile stretches without seeing another living soul. Including police. The majority of the roads are wider than our dual carriageway roads, and the surface was all perfectly smooth with no pot holes.
See these pictures below, I didnt take these, I found them when I got back from France, but they sort of highlight just how good that road is....
These 4 pictures below are ones I took, and you can sort of see the quality of the roads in them.
The moral of all this is just dont bother with Northern France. Really. And the roads in the south are wide, smooth as a baby's butt, fast, winding and WELL worth visiting.
It is so dull. It is really flat, and 95% of the roads are dead straight. You will waste a lot of fuel and toll charges getting to the south of France. The only positive is that there are some really really long straights with no one around, and you can max your bike very easily. We went past a police speed check whilst doing over 250km/h (about 155 I think) and sh1t ourselves.
I didnt ride through the pyrenees mountains in Spain, but I am told by people who have that they are just as good as the Alps.
My GF and I are going later this year. Ferry from Portsmouth to Bilbao and somewhere between 5-10 days in France. Maybe make a trip of it and get a group?
so what do they do if you can't pay. Take your bike, stick some Onions around your neck and tell you to walk home. 
