Among the controversies involving Riefenstahl the estate may throw light on is her feature film Tiefland, for which 122 Sinti and Roma extras were personally selected by Riefenstahl from two holding camps.
He lays an array of sepia portraits of the propagandist Leni Riefenstahl across the table of the workshop of the Museum of Photography in Berlin.
Among the advisers to the project is Rainer Rother, the artistic director of the German film archive and a Riefenstahl biographer.
Derenthal, the museum’s director, will soon be in possession of all 700 cases containing the estate of Hitler’s favourite film-maker and neo-Nazi icon.