I've never been there, but here's an international forum's France section:

http://www.internationalsexguide.info/forum/forumdisplay.php?182-France

Try this site, Punterlink.  Punterlink is London, UK based.  But they have a Paris page.  
100 EUR = 135.00 USD


Addendum.
This  lady caught my eye.

http://www.eva-escortgirl.com/


-- Modified on 1/19/2011 9:33:22 AM

Thanks everyone.

Saw two wonderful ladies from this agency last spring. Booking was painless and efficient. Ladies were as advertised - discounting for glamour shots. Only exaggeration might have been their command of english.
russian-girls-for.me
YMMV but these ladies were over the moon to see an American. I don't know if it's a culture clash but they both rejected the myth of Frenchmen as great lovers. They each expressed contempt for their hygiene and roughness.
Be sure to check if your mobile device will work in France. If not, you can buy a sim card for many phones with some minutes for about $35.