This is a British film I believe. It's set in World War One, and though there's some war action, it is mostly a drama (with a modest sex scene).
A decorated British war hero who is also a rising star in poetry, has produced a dissertation denouncing Britain's involvement in the war.
Great Britain was pledged to defend Belgium whom the German Kaiser overran to attack France.
The war was fought much on French soil - as was often the case for the European theaters in both World Wars.
The main character is a military psychiatrist, who is supposed to make their hero recant before he embarrasses all English aritocracy. But the doctor's experience in treating the shell-shocked survivors of the trenches in Europe, wind up shell-shocking him, and he weeps for the fate of these men. His duty is to get them mentally fit to return to the trenches and die for Britain's war effort. As World War One drags on, there doesn't appear to be anything sane about returning to the trenches.
The music's good too - a Scottish tragic theme for the opening and closing credits is quite memorable.