In 1894, France's government and army already were struggling with a series of damaging scandals when a janitor discovered papers in the wastebasket of a German military attaché indicating a traitorous French officer was spying for the Germans. French military leaders quickly found what seemed like a perfect way to weasel out of the mess. They framed an obscure army officer, Capt. Alfred Dreyfus, as the traitor, possibly figuring that he made a good fall guy because he was Jewish. (Anti-Semitism, sadly, was rampant in 19th-century France). Despite his protestations of innocence, Dreyfus was sentenced to life imprisonment at Devil's Island in South America.
When the chief of military intelligence, Lt. Col. Georges Picquart, uncovered evidence that a Maj. Ferdinand Walsin-Esterhazy was the real spy, his superiors removed Picquart from his post. That's when Emile Zola, the famous French writer, published an expose, "J'Accuse," which irked the military so much, it had him indicted and convicted of libel, forcing him to flee the country.
But the public outcry stirred by Zola grew more intense after another army officer discovered that the conspirators had planted a forged document in the file with the authentic evidence to help convict Dreyfus. He finally got a new trial, and despite a confession from the forger, a military court convicted him again and sentenced him to 10 years' detention. The French premier finally stopped the absurdity by pardoning Dreyfus in 1899 [sources: Encyclopedia Britannica, Jewish Virtual Library].
The Dreyfus affair didn't totally eradicate anti-Semitism, but it marked the beginning of a new, more egalitarian French society [source: BBC News].