Der Boxprinz is a german Documentary about the boxer Norbert Grupe, known as the Prinz von Homburg (Prince of Homburg).
The film goes between 1999 and 2000 and was filmed in Hamburg, San Francisco, Miami, Los Angele...展开s and Bieberach. Gerd Kroske shows the boxing environment of the 60's and 70's and a portrait of the boxer Norbert Grupe, who became famous because of his scandalous boxing stile and his involvement on the criminal scene of Hamburg-St. Pauli. Clips from box fights (amongst other against gegen Piero de La Papa; Óscar Bonavena) and opinions and storys from old friends give impression about Norbert Grupe and his time.
The film became popular in Germany due a scene with Stefan Hentschel, when a troublemaker gets slapped in front of the camera.
That scene it's actually how I knew the film existed. Here it is: