La Terra Trema (1948)
Clips from this are shown as part of the documentary.
A Visconti impersonator is caught and the inspector mentions seven of Visconti's films, including this one.
The Movietitle can be seen on a list in this Movie
Footage from this film was shown in this documentary.
The opening shot of the movie within the movie exactly mimics the opening shot of Visconti's La Terra Trema (a neorealist film) where the fishermen return and the bell tolls