There's a nice restaurant at Orly called Chez Franciose that has great food and not terrible prices, they are quite attentive and the restaurant is small and quiet, perfect for dinner conversation. I would reccomend the set menu, everything my husband and I ordered was fabulous and was beautifully presented. It was a flawless meal, appart from a noisy American in the back of the restaurant that was bragging about skiing. :P
There is also a great little place near Notre Dame, though I cannot recall the name. They have english menus available and the restaurant consists of 3 tiny, rustic rooms jam-packed with tables and chairs. You will find many tourists there, but the menu is distinctly and unapolgetically french (escargots, beef bourginon, frog's legs, etc.). It is small, but there should be a chalkboard outside with the daily specials, they open around 5 pm and are next to a souvenir shop that has postcard racks on the sidewalk, next to the restaurant's door. Order the Beef Bourginon, it is a specialty of the restaurant and is the best I've ever tasted.
There is a wonderful cafe in Paris also, the somewhat famous Cafe de Fleur, which has awesome omelettes and the world's best hot chocolate. Sit outside if you don't like cigarette smoke. I highly reccomend the hot chocolate though, it is rich and creamy and will put all others to shame. I have not ordered a hot chocolate stateside after tasting this one.
If you like crepes, the best place for them is the street vendors, there are several around Notre Dame. If you order a chocolate crepe though, don't be surprised that it will be Nutella. ^_^
There are also some really unique places in Monmartre, next to the Sacre Coeur. The neighborhood is full of artists and bohemian types and the restaurants and cafes tend to reflect it. It's also a great place if you want to just have a cup of coffee and enjoy a nice view of Paris, the sunsets can be spectacular!
Don't be afraid to explore on your own though, almost anywhere you go in Paris is going to have great food 9provided it's not fast food), and if you want a real adventure, order a pizza from one of the french pizza shops, they are deliciously different. Have fun! ^_^