... and I've seen a lot of them, in particular the precodes.
Warner Brothers did make heavy use of Paul Muni in the 1930s, particularly in their prestige pictures, capitalizing on his ability to completely physically transform into a role, and he uses that talent here, where he plays Emil Zola. The odd casting includes two actors well known as portraying villains - Joseph Schildkraut and Gale Sondergaard - as Captain Alfred Dreyfus, the wrongly accused and convicted member of the French army and his faithful wife, trying to find somebody who will help him, even after he is shipped out to Devil's Island. They are the only two completely likeable characters in the film, with the images of other treacherous characters they had portrayed somehow erased by their performances.
Even Zola is not likeable through the entirety of the film. He starts out likeable, shown in his youth, looking for, finding, and writing about topics on injustice, but then he grows complacent as he ages, to the point that when Mrs. Dreyfus comes to him for help when he is late in life at first he resists her plea. But her case is compelling and he quickly changes his mind.
The other thing I noticed in this film - It sure is good to be an American and have protections for free speech. Throughout his career Zola comes up against state censors who try to suppress his writings if they make France look bad. Then whenZola takes up Dreyfus' case he is prosecuted for "criminal libel" which is basically a law against making France look bad, with even the judge in the matter seeming to be in cahoots. No wonder the officers involved felt free to keep Dreyfus imprisoned even after they found out who the actual spy was.
I'd recommend this film as a worthwhile watch, but I'm not sure it was the best film of 1937. I'd probably give that honor to The Awful Truth.