First important fact: this movie, about the first year of WWII when Hitler took over France, was released a month before "Casablanca." It does not compare in most ways with the drama, the humor, the writing, the music, the velocity, and the legendary actors of the more famous movie. But it is a very good movie with an interesting early pro-American, pro-French message. Joan Crawford crackles as much as she can in a topsy turvy role, going from spoiled and frivolous rich woman Michele de la Becque to (briefly) a refugee to, finally, an ordinary woman fighting with all her heart for France.
There are two male actors with important roles and they couldn't be more different. One is Michele's lover and fiancé, played with a cultured perfection by Philip Dorn, a Dutch actor who pulls off the pan-Euro, mostly French aristocrat and businessman well. Opposite him in every way is the homey, tough, humble American who shows up halfway through the film, John Wayne. I don't know if this really makes sense in the film, but I can see it on paper, since Wayne played a non-cowboy merchant seaman in the terrific John Ford film which prefigures this one in some ways, "The Long Voyage Home." He doesn't seem as wily and smart as a fugitive from the Nazis would have to be, behind the lines in occupied Paris, but he at least plays the role of an ordinary American ready to help the French, and this is the political message throughout.
In fact, the movie borders on a brilliant propaganda device, putting message ahead of plot now and then, just perceptibly. Crawford is so good even her speeches make a convincing case, and I'm assuming American audiences cheered her on by December of 1942 when it was released (on Christmas day). The scenes of the Germans taking over Paris are always horrifying, and they are again here. There is even a deliberate homage to Soviet director Eisenstein when a baby carriage runs off after the mother is killed by gunfire.
But back to "Casablanca." It's an interesting problem to solve, feeding the American audience worried about the war and about U.S. involvement. Because Hollywood was both a symptom of public opinion and a shaper of it, and these are two rather different kinds of films with very similar messages. Director Jules Dassin, who is not French but American, had just started making films in 1941, and there is a sense of expertise at the expense of intuitive magic. "Reunion in France" is strong, smart, and convincing. But it doesn't sizzle or build the aura of the time like it could. And yet, in its defense, it has no perspective at all on the events, since it was made while they were unfolding, even before they were unfolding since it has to anticipate to some extent how the film will settle six months after being written and shot. Watch it. It's really good.