Being interested in military history for many years, the Dreyfus affair is something I recall from school; the story of how an officer of the French army was falsely accused of selling information to the Germans and sentenced to prison on Devil's Island off the coast of South America.
Dreyus was sentenced because he was a Jew, even though the overwhelming evidence proved his innocence, from the start his supporters had a feeling that somebody higher up the ranks was responsible for the leak, but the army needed a scapegoat and Antisemitism was a growing concern in France, so who better than a Jew to take the blame.
Dreyfus served 5 years of a life sentence before he got another 'trial,' mainly through pressure from the press and Jewish public opinion, as many of the Jews held influential positions(Marcel's father was a respected doctor), but the second trial was no more than another sham and Dreyfus got a 10 year prison sentence, which was commuted, he later served in the army-after being given a full pardon, when many of the real culprits had come to trial, some committed suicide rather than shame the army.
What I find most enthralling is to read an account from a person who witnessed the events and the aftershock it caused, this public show of Antisemitism split the population, people formed new friendships not through social status, but through national pride and belief in justice.
The press was so controlled by the weight of the Generals that even the respected writer Emile' Zola got blacklisted and had his work banned, he had to publish his work J'accuse as pamphlets among the students.
As Marcel put it so adroitly "Old friends became new enemies and old enemies became new friends."