Hoping to make a career in gangsterism, Jojo, a young rascal, demonstrates his know-how by stabbing a passer-by in broad daylight. However, the victim was making a film, and the crime was recorded. In charge of the investigation, Superintendent Bernard, a fine sleuth who takes himself for Maigret, has the sequence projected and extracts a portrait of the murderer. One of his men thinks he recognizes a clown from the Médrano circus, who is immediately arrested. But the latter has a twin brother as a partner: each accuses himself to exonerate the other. Two suspects are better than one, we keep them both behind bars at the Sûreté. However, the real murderer is still running: he is a double of the antipodist twins. It takes the intervention of Titine - a lady of light morals, but with infallible memory, who spent the night with this third thief - for the light to shine. Only a woman, preferably venal, was able to disentangle the truth from the false, the reality of its simulacra