The EasyExpat Paris guide (http://www.easyexpat.com/en/paris.htm) lists several places under the language section (http://www.easyexpat.com/en/paris/schoo ... ourses.htm):

UFR Didactique du français langue étrangère
Université de Paris III
13, rue de Santeuil
75005 Paris
Tél : 01 45 87 41 21

Université de Paris-Sorbonne
47, rue des Écoles
75005 Paris
Tél : 01 40 46 22 11 postes 266 à 275

Alliance Française
101, boulevard Raspail
75006 Paris
Tél : 01 42 84 9000

Institut de Langue et de Culture Françaises
Institut Catholique, Summer school
21, rue d'Assas
75006 Paris
Tél : 01 44 39 52 68

Cours Municipal d'Adultes
Département langues vivantes
9, rue Perle
75003 Paris
Tél : 01 49 96 68 90

France Langues
2, rue de Sfax
75016 Paris
Tél :01 45 00 40 15

Département d'études françaises
pour étrangers
Université de Bordeaux III


Centre International d'études françaises
Université de Lyon II16, quai Claude-Bernard
69365 Lyon Cedex
Tél : 04 78 69 71 35 et 04 78 69 71 36

best of luck!

 

There are of course some typical places as texkourgan suggested, however I'd recommend the place I took French classes, Nouqa Langues (www.nouqa.fr). They specialise in teaching languages, and it shows from the first class you take, not only that but they are extremely nice, and fun. I loved my professor and French lessons there - I learned a lot and I still use the songs, vocabulary, everything I learned there! That's the children's site I believe but they have classes for students, employees, etc. Definitely helped me socialize here