Cannes, France was a coastal French town where Jaime Sommers and Pierre Lambert thwarted the plans of the head of a art forging ring named Michael Beaumont to sell a DeJon painting to the Corsican mafioso, Moreau.
Jaime, posing as the Swedish wife of a rival bidder, boarded Moreau's boat and proved the painting a fake by wiping its not-yet-dry paint off with her fingers. This act exposed Beaumont as a fraud, and compelled Moreau to hold him in a lower cabin. Jaime offered to break Beaumont out of his makeshift "jail" if the criminal would turn over complete records of his illegal transactions. (The DeJon Caper)