My wife and I spent a pleasant evening on Saturday nite (June 3) at a tiny little restaurant on the Ile St. Louis in Paris called Le Relais de L'Isle that also features piano jazz, sometimes even a small trio or quartet. The entire restaurant seats but 24 people, it is VERY small.
On this particular evening, the pianist was very good, though his music selection strayed rather far from the jazz I'd hoped for, with the likes of Beatles, Elton John and Billy Joel tunes comprising much of the repertoire. While it was disappointing that the soft piano jazz and blues for which I'd hoped would accompany our dinner was scarce, it was still lovely.
Even the food was surprisingly good quality, I feared it would be inedible, but it was good, if not great. I had the magret de canard, which was tasty. The wine list was decent, and our total bill came to about $240 USD....not cheap, but I bought expensive wines, your bill could easily be $100-$150 cheaper if you so chose.
I've never seen a review of this restaurant, so I thought some of you might find this useful. BTW, this little jazz restaurant is located next to the notorious Nos Ancetres de Gaulois, and the drunken fool from there who accosted my wife as we were leaving Le Relais is likely still, um, "digesting" his meal from that establishment.