It's a small entrance next to the arcade entry, in the fabulous Lucerna building that is a Landmark, including classic theatres and cinemas, shops and cafes, artwork, etc, and you could not possibly be in a more convenient location, right in the centre of everything, right next to the tram, and straight down the main boulevarde from the main train station.
I got a very reasonable price for Junior Suite room, with space and all standard amenities, as well as opening windows looking down on the main boulevarde.
It's called a three-star, but it's better than that, and as the most useful, practical, value for money, in the perfect location to get to anything you want to do and see, I can't see any reason I won't stay here again