That being said, what makes La Grande illusion remarkable isn't the officer's sense of duty, but rather Renoir's exploration of humanity in the midst of war. A major theme of the film's first half revolves around war's ability to realign traditional class structures. That is, it levels the field, for there are no aristocrats or peasants in foxholes, only soldiers[1]. Still, there's a natural tendency to cling to those old labels, even in a concentration camp.

Rauffenstein, recognizing in Boeldieu a fellow member of high society and wishing to not be viewed as a "German barbarian", affords Boeldieu certain liberties not available to the likes of Maréchal and Rosenthal. He invites Boeldieu to join him for dinner and is willing to trust his honesty, rather than employing the usual methods of searching a prisoner's quarters.

They form a sort of friendship based on a mutual civility, enemies finding a small corner of kindness in the brutality of war. But this being war, Boeldieu is forced to use this kindness as an opportunity to facilitate an escape for his countrymen and fellow officers. It is a selfless act that is both daring and grand. Once again, duty reigning supreme.

In the end, you realize that on so many levels La Grande illusion isn't about war at all, but instead is about humanity's ability to connect with each other despite their numerous differences, that two people in a room, stripped of their titles and their nationalities and their wealth and everything else, are simply two people in a room and they must learn to see each other for who they are, not what they are. It matters little if you're French or German or British or American because all that is superficial and man-made, just like the lines on the map that determine where you are.

Are Maréchal and Rosenthal any more free recovering in a German farmhouse then they would be in Switzerland, or are they just on the wrong side of an imaginary line? Perhaps it's fitting that in World War II, when the Germans invaded France, Goebbels had the film confiscated in an attempt to destroy it, but Frank Hansel, a Nazi officer, managed to smuggle it to Berlin and preserve it for future generations. A brave and selfless move by Hansel, to be sure, a case where life imitates art and a German saves the legacy of a Frenchman, even though they are on different sides of an imaginary line.

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[1] Of course, you could argue that aristocrats don't end up in foxholes nearly as often as peasants, but that's an altogether different issue.

Starring: Jean Gabin, Erich von Stroheim, Pierre Fresnay, and Dita Parlo
Written by: Jean Renoir and Charles Spaak
Directed by: Jean Renoir
NR, 114 min, 1937, France