On July 4, 2003, only a few minutes after the arrest of Yvan Colonna, who had been on the run for four years, the Minister of the Interior and future victorious candidate for the presidential election interrupted a public meeting to announce that the "assassin" of the prefect Claude Erignac had just been arrested. At this moment, the tone of the trial that was to follow is set. It will not vary. Yvan Colonna's trial is a political trial and he will be condemned not because the police investigation, and subsequent investigation, will have made it possible to demonstrate his guilt, but only because the State has found no other culprit. The author deconstructs the trial of Yvan Colonna, from the scene of the crime to his conviction. It examines the established facts and the gray areas of the procedure, exposes the irregularities committed and the insufficiencies of the accusation: the absence of reconstitution, the small arrangements with the evidence, the alibis and the witnesses. And, finally, it is the shortcomings of justice itself that he points to.