Just a heads up, if you are leaving via charles de gaulle airport, make sure you MULTIPLE HOURS extra to leave, since that is what it's been adding to get through immigration or passport check. We were delayed by almost 4 hours last month, making that extra hour+ that we thought we had, useless. It's been a real issue there, and only getting worse.
Coquilles St. Jacques? I've only ever had them in Paris, on one visit. The restaurant was gone when I went back years later, and I've never seen them again. To die for.
Oui! The restaurant was Les Cocottes near the Eiffel Tower. I had done about six hours walking by that point and was ready to treat myself. There may have been a slightly champagne-tipsy hour of walking back along the Seine in the sunshine to my hotel near the Sorbonne.