French Female Vocalist Jazz Blues Suggestions ???

Coralie Clement - Bye Bye Beaute

Perhaps a bit too pop, but an excellent voice

Miss Kittin and the album "I com" do a great version of 3ème Sexe, sung in French. A very delicate and melodic pop song from a real popular techno singer.

You can sample it here: http://www.amazon.com/exec/obidos/tg/detail/-/B00022XE2M/ref=pd_sim_music_1/002-7716851-1189634?v=glance&s=music

Madeline Peyroux ..... as several other above have recommended above. Sultry, sexy, & bluesy.

I'm actually listening to her right now ;-)

Patricia Kaas definitely fits the description of what you're looking for...jazz / Blues influence and very French, her debut album "scene de vie" is quite good. goes back at least 10 years or so.