If in Paris (or even Japan), don't miss out on Pierre Hermé and Christian Constant. Both have taken chocolate and pastries to another level with ingredients like ginger, frangipani, verbena and isphahan.
Apparently Pierre Hermé started in Japan, and now he can only be found there and in Paris. It would explain why I saw a bus load of Japanese tourists queuing outside Hermé's just after I had done my shopping there.
In the guide book First Class, Christian Constant has been rated the best chocolatier in Paris, with Pierre Hermé at number 6. If you want chocolate alone I would recommend CC, a man that travels the world in search of new exciting flavors to incorporate into his chocolate making, however if you are into pastries, PH is your man.