Depending on exactly where your hotel is, you could investigate restaurants on the rue Lamarck and rue Caulaincourt. If you read French, you could pick up a "Guide du Routard" on Paris restaurants. They have listings by price category and are fairly reliable. Also, non-French restaurants (i.e. Italian, North African, oriental, etc.) are often less expensive. If you post what kind of food you like, I might be able to suggest something.