Thomas the Impostor (1965)

In the First World War, when Paris is expected to fall to the Germans, the attractive widow, Princesse de Bormes, organises a convoy of cars to evacuate the wounded from the front, and bring them back to her villa in Paris to recuperate. The authorities will not give them passes until an innocent 16-year-old boy, Guillaume Thomas de Fontenoy, joins them and is mistaken as the nephew of the popular General de Fontenoy. The Princess is enraptured by Thomas and her daughter, Henriette, falls in love with him. However Thomas feels impelled to see more of the action of the war.