Does anyone know where to find it?

Adolf & Marlene (1977)
Directed by: Ulli Lommell

In this scandalous film, footage from Marlene Dietrich's early films is combined with documentary footage of Adolf Hitler, along with newly filmed dramatic re-enactments, suggesting that Dietrich was Hitler's secret mistress. Dietrich brought the filmmaker to court to prevent the release of this film, though it was quietly screened at the Cannes Film Festival before anything was resolved.
~ Clarke Fountain, All Movie Guide

Dave Brett
My video archive: http://www.davebrett.com/NonSport.htm