Der Westwall

Der Westwall is a 1939 film about the Siegfried Line directed by Fritz Hippler, the head of the film division within the Propagandaministerium. The Siegfried Line, called the West Wall by the Germans, was a large series of fortifications around the German borders with France, Belgium, Luxembourg, and the Netherlands.

Synopsis from Wikipedia, CC BY-SA 4.0. Everything below written here.