This Mad World.

Parisot, a French spy in World War 1, returns home on a secret mission to visit his mother, and finds that Victoria, the wife of a German general, is billeted in the Parisot home while waiting to see her husband. Victoria discovers that Paul is a spy and, although fascinated by him, plans to reveal his identity to her husband. When the latter is unable to visit her, she attempts to go to the German army headquarters.