Navbox is a great tool for planning flights around Europe. Even better if you can take it with you on a notebook PC and better yet if you have a portable printer for PLOGs etc.
French charts are available mail order from the
SIA much cheaper than UK sources (free postage!).
Personal recommendations in France:
Cannes - exclusively for GA and good value considering the location. Hotel at the airport for convenience but many others in town.
Troyes - good for an efficient and friendly fuel stop. Very good weather briefing office in the building next to the terminal. Hotel at the airport if you need it and the medieval town is interesting enough for one night. Customs available (sometimes notification required).
Annecy - stunning lakeside / mountainside location.
Deauville - expensive taxi ride into lovely Honfleur or cheaper ride to less lovely (but still pleasant) Deauville or Trouville.
You could also consider Italy. Venice San Nicolo is a grass strip just across the lagoon from St. Marks. Nearby Padova has avgas as Venice often don't.