Duval is on the trail of a female con artist who poses as a celebrity buying jewellery, and escapes by being arrested by two fake policemen. After the embarrassment of trying to arrest a genuine princess, checking enquiries at a press agency gives Duval a new lead. A narrow escape in Rome sees the fraudster escape again, but abandon her luggage. Her expensive, tailor-made clothes give Duval another chance when she comes to Paris for replacements.