I will post photos when I go home.
Based on a few CH recommendations I used LaFourchette to obtain a reservation at Au Bon Coin. It is in the 5eme on Rue Collegiate. On Sunday there is no promotion but the prices were ok. 18E for a main and 7E for dessert. The service was fast and friendly. There was only one server and a few full tables but it was obvious that she knows what she is doing. I did not order a starter because I was planning a little food pit stop latter but she gave everyone a small glass of asparagus cream with olive oil and spices. It was excellent! I could have eaten that as a soup. I choose the Sea Bass with zucchini as my main course. The presentation was great, the skin was crisp and the zucchini was properly prepared. The flavors of the sauce blended very well with the moist fish. For dessert, I tried the millefeuille. I was surprised because it did not have many layers and I thought that made it not qualify. But my first taste was extraordinary. When I took the first bite, I was in Heaven. I always like to sample the different components of my dessert alone to see how they stand up and I was a little disappointed in the bites that did not contain the cherries. The flavor was a little too mild and the green cream was somewhat pasty. Not serious flaws but it was perfect with the cherries and okay without. Overall, a very good experience.
Thanks to everyone who has suggested it!