There's a lovely place called Cosy Wine (not sure why - they are French ...). The last time I was there (about a year or so ago) it was still very reasonable at 15 Euros for their menu, which was for three courses. They generally have two or three dishes to choose from in each course. But, unusually, sometimes the starter is served with or on the same dish as the main - don't let that put you off, the only time they have served it to us like that, it was arranged as a kind of platter, and it did work.
The food is not always French - they have dishes inspired by other countries and continents. The cooking is really good (never had a bad - or even average - dish), the house wine is great value and the staff are lovely. Great location too - its in the Place d'Assas, which is a lovely little square near the Maison Carrée.