"Paths of Glory", starring Kirk Douglas, is one of the best antiwar films ever made. Three French soldiers are picked at random to be executed for cowardice; KD attempts to defend them. They're shot, of course, and at the end there's a very moving scene where a captured German girl is made to sing for the soldiers. She strikes up "Der Treu Hussar", a very poignant song, and gradually the weary soldiers join in.
The film was I think banned in France.