We've been here a couple of times during our stay in Paris and shopped for picknicks. The selection is absolutely decadent! We tried various spreads, olives, artichokes, veggies, breads etc and everything was absolutely over-the-top! The staff ist very nice, and automatically answered in perfect English (and one case even good German!) when the noticed we were tourists. The whole breads were awesome too! Nice alternative to baguette! We tried various wines too and all of the were very, very good!
And you can have a picknick in the Jardin du Luxembourg right around the corner!
Cons: absolutely nothing!