We have friends who live in that neighborhood, whom we see at least three times each year, but I have been consistent in forgetting to ask them. On Christmas Eve, I did remember to ask, probably because I had recently passed the queue. Our friends knew.
The downstairs door, which has no sign, gives entrance to an exclusive and expensive restaurant. I forget whether the restaurant takes reservations, and I'm pretty sure I didn't ask the name. I hope that one must say "Swordfish" to be admitted, but I doubt this is so.
There was nobody there this afternoon, more likely because I was by about 4 pm than because it is New Year's Eve.