Well, here comes an update!

I
must add Michel Chaudun recommended by Laidback (and maybe others too) already.
Wow, what a great little shop, what absolutely delicious chocolates, especially the
pavés (cobblestones). Monsieur Chaudun himself was in the shop while we were there. We were absolutely charmed by his chocolate Hermès kelly bag in the window. It was created some 380 times for a special Hermès event. Too cute!

A not to miss place. 149, Rue de l'Université, 7th arr. If I recall that correctly, closed Sun/Mon.
I also visited for the first time Jean-Paul Hévin's first shop located at 16, Avenue de la Motte-Picquet, 7th arr.
http://www.hevinbis.comOnly there, they sell those very paperthin
feuilles de chocolat. One word of caution though, no way to pack them into a suitcase.
To be eaten
in Paris.
Other locations:
http://www.jphevin.com