For this I began to think about other students on a restrictive budget, those beginning their profesionnal careers or simply just those who would like to eat on the cheap.
Already in a previous post, I mentioned the website "La Fourchette": http://flipflopfrance.blogspot.fr/2012/03/advice-la-fourchette.html
Basically a reduction website in which you sign up, choose the restaurant and book in advance for often a percentage discount or a special dinner menu. There is no penalty for cancelling the reservation, no costs up-front and simply allows an easy way to go to nice restaurants at a reduced price.
Of course, there are other options... Every year, the Paris Region hosts a special event called, "Tous au Restaurant", or everyone in restaurants, which enables anyone living in the Paris area to go to restaurants of Michelin Star quality for the reduced price of "Buy one Get one Free": http://www.tousaurestaurant.com/fr/
However, this reduction and special event is only available for a limited time during the year, and unfortunately the 2012 season has passed... in preparation for 2013:
- Book in advance (otherwise there are no spots available)
Other than this, there is always the fun option of eating at the cooking schools in Paris... normally only available during the weekdays (Monday-Friday) afternoons and evenings, however, one can score a 3-course meal for a measly 16€, a steal... if the chef is actually a good one: http://www.lesitemalin.com/loisirs/cuisine/ou-manger/restaurants-ecoles-hotelieres.htm
Otherwise, opt for the "Menu déjeuner" when possible, always try for the "menu" and not "à la carte", which often proposes a discount for taking the main dish and dessert.