Hautnah(1985)

Private eye Dold, a specialist in surveillance tasks, is sent to investigate a Frankfurt bordello boss. He's a pain in the butt for many in the red-light district and is to be overthrown to pave the way for financially strong speculators to lucratively redevelop the area. Dold, who always saw his work as morally justified, comes to doubt the rightness of his actions far too late.