Le Baron

I went there a few times with friends, it's a peculiar place where creative/arty/fashion types mix with ultra-posh wealthy locals. It used to be an upmarket brothel before it was converted to a bar/club. It's not very big inside, you can fit around 200-300 people there so the doorman can be picky at the entrance. Wearing smart clothes will help you blend with the locals, who tend to be ridiculously arrogant, and therefore comical.
The walls are decorated with images of naked ladies photographed early in the 20th century, all in rather good taste, nothing provocative really.
Also worth noting is SMS-mirror by Robert Stadler, where people can send messages to a mirror installed by the bar. Use this number:0033619292662 but beware, you number will appear after the message you send!
Other than that, it looks like a 70s club with leather couches. A small area is available for dancing, which gets packed on weekends, be sure to catch DJs Rik and Ze, spinning some classic 80s punk-rock, and other funky stuff.