April in Paris
You mentioned earlier that you'd be staying at Hotel Lutetia in the 6th.
We stayed close to there a few years ago and ,besides the usual suspects, we especially enjoyed three places within walking distance of your hotel.
Excuse me for cutting and pasting here as I thought you'd like some specifics rather than a short cut to something I wrote for another couple...
For Chinese we like Le Canton 5 rue Gozlin, 6th. We stick pretty much with the seafood across the board there. Keep this tip aside because they are open on MONDAY! and most good places are not. BTW they are NOT open on Sunday.
For Sunday we went to a small Italian place on Mabillon and had the owner pick out two dishes, salads and a chianti for us. It was great! The bakery next door is pretty good, too.
To be with lots of people, moderate prices and decent food every time, and to have a good time, we go to Bistro de Breteuil 3, Place de Breteuil. The tables are very close and you just get swept up in conversations and instant friendships with people from everywhere, including the fantastic apartments in the neighborhood. Lots of embassy and international corporate people go there.
Finally, I suggest that you read the chowhound thread entitled, "Poor and hungry visitors to paris" at http://chowhound.chow.com/topics/6076... The title may not apply to you, but the advice is still very good.
...and adding to these good suggestions. You are nearly in rue Cherce-Midi, head along there (towards 15eme) and you get to Josephine Chez Dumonet which is a great old style Bistro. Head the other way and you have rue du Seine and the good wine bar called Fish. Both reasonable strolls which pass a few other interesting cafes and restaurants. Le Nemrod for example is a good spot for lunch as it is packed with shoppers from Bon Marche.