Paris, 1889. A few days before the opening of the Paris World Fair and Mr. Eiffel's tower, The Twelve Detectives, an organization of the world's best sleuths and their assistants, meets in the City of Light in order to bring together a collection of objects from their most celebrated cases to exhibit at the fair. Only one member of the organization cannot attend, the Argentinean Renaldo Craig, but he has sent his assistant, Sigmundo Salvatrio, as his representative.

The trip is an initiation for Sigmundo, who finds himself assisting detective Viktor Arzaky, a Polish expatriate living in Paris. Arzaky is investigating the death of his colleague, and greatest rival, Louis Darbon, who has fallen to his death under mysterious circumstances from the Eiffel Tower. The initial inquiry expands and Sigmundo finds himself searching the Paris underworld of occultists who oppose the building of Eiffel's structure, and following the leads of other deaths with connections that increasingly seem to link back to Arzaky.

The Paris Enigma has a clever narrative that De Santis plays with in order to highlight various traditions of detective and crime fiction, like cliched sidekicks and methodologies. It is a wonderful smorgasbord of classic mysteries and their detectives, and provides the reader with great fun in working to solve the crimes and identify the literary references.