The Dreyfus Affair is a political scandal that divides the Third French Republic from 1894 until its resolution in 1906.

'The Affair', as it is known in French, has come to symbolize modern injustice in the Francophone world, and it remains one of the most notable examples of a complex miscarriage of justice and antisemitism.

The role played by the press and public opinion proves influential in the conflict.

The scandal begins in December 1894 when Captain Alfred Dreyfus is convicted of treason.

Dreyfus is a thirty-five-year-old Alsatian French artillery officer of Jewish descent.

He is sentenced to life imprisonment for allegedly communicating French military secrets to the German Embassy in Paris, and is imprisoned on Devil's Island in French Guiana, where he spends nearly five years.

Evidence comes to light in 1896—primarily through an investigation instigated by Georges Picquart, head of counter-espionage—which identifies a French Army major named Ferdinand Walsin Esterhazy as the real culprit.

When high-ranking military officials suppress the new evidence, a military court unanimously acquits Esterhazy after a trial lasting only two days.

The Army laysadditional charges against Dreyfus, based on forged documents

Subsequently, Émile Zola's open letter J'Accuse…!, stokes a growing movement of support for Dreyfus, putting pressure on the government to reopen the case.

In 1899, he is returned to France for another trial.

The intense political and judicial scandal that ensues divides French society between those who support Dreyfus (now called "Dreyfusards"), such as Sarah Bernhardt, Anatole France, Henri Poincaré and Georges Clemenceau, and those who condemn  him (the anti-Dreyfusards), such as Édouard Drumont, the director and publisher of the antisemitic newspaper La Libre Parole.

The new trial results in another conviction and a ten-year sentence, but Dreyfus is pardoned and released

In 1906, Dreyfus is exonerated and reinstated as a major in the French Army.

He serves during the whole of the Great War, ending his service with the rank of lieutenant-colonel.

He dies in 1935.

The affair from 1894 to 1906 divides France into the pro-Army, mostly Catholic "anti-Dreyfusards" and the anticlerical, pro-republican Dreyfusards

It embitters French politics and encourages radicalization.