The Dreyfus Affair still reserve some surprises. Three researchers have reopened the archives conserved Service History of Defense and the National Archives to reconstruct the secret dossier produced by the Statistics Section - the French intelligence service and military espionage against - to overwhelm the captain Dreyfus. Transmitted to the sole judges of the War Council, cache accused as has its defenders, the secret dossier was increased false and incoherent parts as and grew louder as the protest against the unfairness of the process and applications revision. Its production (nearly 500 documents) betrays obsessions officials of the Section. A xenophobia and antisemitism are added the fear of cosmopolitanism and homosexuality, recalling fantasies and adversarial procedures of the Inquisition. The three researchers not only to reveal a story ignored until present official narratives. They renouvelent the method drawing on techniques developed by medievalists for the analysis of ancient manuscripts and processes. And we plunge to the rhythm of a spy novel in the heart of Paris of the Belle Epoque.