French President Jacques Chirac has led a ceremony marking the centenary of the rehabilitation of the Jewish army officer Alfred Dreyfus.
The French president and descendents of Dreyfus
The case triggered a national crisis in France in 1895, when the captain was convicted of treason on trumped-up spying charges.
Mr Chirac said his rehabilitation was a rejection of anti-Semitism and a victory for human rights.
But he warned that these values could not be taken for granted.
"The fight against the dark forces of intolerance and hate is never definitively won," Chirac said at the ceremony in Paris' military academy, where Capt Dreyfus was stripped of his rank and then vindicated 11 years later.
"We must remain vigilant," he said in the speech broadcast live on French television.
Relatives of Alfred Dreyfus attended the ceremony, along with relatives of the novelist Emile Zola, who campaigned on behalf of the captain.
The Dreyfus Affair, as it is still known, left an indelible mark on the French nation.
It began in 1894 with a letter intercepted by French army intelligence intended for the German military attaché in Paris.
Within weeks the government pointed its finger towards the young officer.
Capt Dreyfus was arrested, convicted on charges of treason, publicly stripped of his rank and sent to a prisoner's hell, Devil's Island, French Guiana.
For 12 years, Dreyfus and his supporters fought to expose the anti-Semitic conspiracy that led to his conviction.
Dreyfus returned to the army and was awarded the Legion of Honour, one of France's most prestigious distinctions.