Decent meal, casual atmosphere - please help.

Dear Chowhounds,

This is my first post, it my be a little too detailed... please forgive me.
Will be in Paris this Sunday to Wednesday and would be very grateful for any input you may be able to give. We (party of 2) are looking for places with good food, of course, but we are more looking for an overall lovely experience. Casual places that make us leave satisfied and happy. In New York we like to occasionally visit places like Eleven Madison Park, Jean-Goerges or Le Bernardin
BUT we feel much more comfortable at places like Perry St., The Little Owl, Spotted Pig, Gramercy Tavern, Fleur de Sel (closed unfortunately) etc.
Unpretentious and casual places where you can have a decent meal and this is what we are looking for in Paris. We are on vacation so we have time and we
don’t mind waiting for courses as long as they keep the wine flowing 

We do like good food, but the focus this time really just is on having a good time. Hope this doesn’t disqualify us…

The challenge really is that many of the nice places are closed on the days we visit. Well, this is what we are thinking:

Sunday
Sundays are difficult in Paris. We arrive in the early afternoon, too late for lunch, and we plan to stroll around the Marais and then have an early dinner.
Is Bofinger, Chez Julien or Les Philosophes in any way acceptable?
If not, we thought about L’Ardoise which is close to our hotel, Ritz Paris. Any other recommendations in the Marais maybe? I have not really a clue for Sunday...

Monday
We thought about having one nice lunch without breaking the bank either at Taillevent or Le Cinq as they all have a lunch special and they are open on Mondays. Will they have wines in or below a EUR 50 range?
I realize that Souphie highly recommends La Grande Cascade but it seems to be a little out of the way and it looks a little old-fashioned (but then again you are the expert, Souphie). I find Pre Catelan more appealing but it is closed on Mondays, unfortunately.

For dinner we thought about going to Fontaine de Mars as we love Steak Tartare and it’s their special on Mondays. I hear it is a very reliable restaurant and need to have a good Steak Tartare once while we are in Paris.

Tuesday
Light and casual lunch on the left bank preferably near Musee Rodin.
Tanta Marguerite or Les Cocottes?

Dinner at Le Chateaubriand.

Wednesday
Late lunch at Chez L’Ami Jean, before leaving home.
Or would you rather recommend going to CAJ for a late Dinner on Tuesday instead of Chateaubriand? I hear the atmosphere is fun late night but I am just afraid I will be soooo full. But I guess that’s the price one has to pay… we don’t come to Paris to go on a diet anyways.

Thanks heaps for your input,
Maic

tigermaic in France