A unique blend of musical, film-noir and comedy - with a few sex scenes thrown in for good measure. The only other film I can think of with a fairly similarly wild and madcap mixture of themes and clichés is the French movie Billy Ze Kick - but that has a more surreal and quirky approach.
Not that this film would not be surreal or quirky. The humour is at times quite subtle, at other times blatantly in your face - and often crossing the border to offensiveness. To give an example: in the post-coital chit-chat with a prostitute our hero Max Müller encourages her to reveal who was responsible for a recent murder, using the words "Schiess los!". Literally, this phrase means "Shoot!" in German, and that is exactly what a hidden assassin does in response. In other words - this beautiful lady was sacrificed for a pun.
Müllers Büro is also one of the very rare examples of films with funny sex scenes. Larry's romance is accompanied by the song "Ich will mehr" (I want more) - while the song perfectly underpins the action, the meaning of its words changes a couple of times, hinting at the end at Larry's inability of providing any further service. The film's main love scene between Max Müller and Bettina Kant lacks such subtlety - this is jaw-dropping stuff, especially when Bettina's singing slowly transgresses into moaning, of course all in the rhythm of the music.
Unmissable, unless you are one of the easily offended.