Blue Lagoon is excellent, especially if you like fish specialities. The setting is beautiful - dim lighting and excellent theming backing on to The Pirates of the Caribbean ride! - spectacular.
Also, Walts on Main Street USA offers excellent food in small themed rooms overlooking the main street. This is a great place to come during a parade and there are two menus to choose from. A set cost menu and a separate menu. There is a wide choice of food and the staff, IMO, were excellent.
There is also Auberge du Cendrillion which is only open for lunch.
They can get fairly busy, so make sure you make a reservation in advance, especially if you are travelling in peak times.
If you are willing to splash out a little bit then there are many wonderful restaurants within The
Disneyland Paris Hotels.
California Grill is stunning. It is situated within the Disneyland Hotel, overlooking the theme park and serves a wide-array of food from delicious fresh meats to other specialities. The service is excellent and the theming is quite casual, but relaxing. It also has a large wine list.
A bit cheaper, is the Inventions Buffet within The Disneyland Hotel - this is one of our favourite restaurants - a delicious fresh buffet with seafood, meats and lots more. It is excellent value for money IMO and also overlooks the park.
You can walk to these two from the parks within about 5-10 minutes.
Again, make sure you make reservations if travelling during a popular time.
Richard.