It's called Boca Mexa (127 rue Mouffetard) and I recently went to check it out with a friend.. I had actually first noticed it in the fall, but I just finally went to try it out and I am VERY excited about this place!
The set up is very similar to Chipotle...you pick what form you want (burrito, taco, quesadilla), the meat you want (beef, chorizo, chicken or vegetarian) and what other items you want (rice, beans, type of salsa, cheese, etc). For 8.50 euros you get your choice of main dish with a side dish (chips with a choice of guacamole or salsa, Mexican soup, etc) and a drink. Not too bad and definitely plenty filling!
inside the restaurant
Even the serving style is very similar to Chipotle. Burritos wrapped up Chipotle-style in aluminum, sides of chips served in brown paper bags, etc. The similarities are unbelievable. And I must say, even the taste is very close to Chipotle. Not exactly the same, but not too far off and definitely close enough to fulfill any Chipotle craving I may have while living abroad.
When you go, be sure to ask for a carte de fidelité which they will stamp each time and after a certain number of meals you get some free stuff.
Also interesting for us expats craving Mexican foods is the fact that they sell some Mexican products in the store including a variety of hot sauces.
the wall of hot sauces
Definitely worth it to check this place out for the food and the Mexican products!