The Dreyfus affair was a political scandal that shocked France in the 1890s and early 1900s.
In November 1894, a French artillery officer, Capt. Alfred Dreyfus, was convicted of treason and sentenced to life imprisonment for supposedly communicating military secrets to the German embassy. In 1896, new evidence emerged suggesting that Major Ferdinand Walsin Esterhazy was the real culprit. However, this evidence was suppressed by military authorities and Esterhazy was acquitted. Meanwhile, the French counter-intelligence department produced false documents further asserting Dreyfus's guilt.
Public distrust of the proceedings came to a head in January 1898 with the publication of J'accuse, Émile Zola's open letter, in a Paris newspaper. The fact that Dreyfus was of Jewish descent led many to argue that he had been convicted due to an anti-semitic bias.
The case was reopened, and the retrial of Dreyfus split France. Eventually, all charges were dropped and Dreyfus was reinstated in 1906.