You may want to try to have a meal at Cafe de la Paix, across from the Opera House. It is a great sidewalk cafe and "People watching" place. Right down the street from there is The Capucine, another nice cafe, less expensive and fun. You will have no problems having a great time, there are so many places very close!
I was in Paris this past week-end and did look around for a couple of nice relaxing places that you might enjoy. I previously mentioned Cafe De la Paix, which is still a favorite of mine. Right across from the Louvre Hotel is a great sidewalk cafe. Go to my new update for pictures and names on my new post. You also may enjoy the Louvre Rest. it is very reasonable and pleasant.
Suggest you pose your questions also on Trip Advisor...I found hundreds of responses and have planned our upcoming trip using the suggestions there as well as here. Please post your experiences. We're staying there in November and will be looking for your report