The use of fake - but legal - banknotes in France is rising, warn police, with many copies available to buy on the internet.
Banque de France seized more than 2,000 of such notes last year, with this figure considered to be “much lower than the reality” of notes in circulation.
The notes in question are legal as they are stamped with words such as "poker", "specimen" or even "Disneyland," meaning they do not constitute counterfeit money.
They can be bought fairly cheaply online, said commissioner William Hippert, head of the French information, intelligence and strategic analysis service on organised crime (Sirasco).
Police have warned that the fakes are now increasingly being used in scams worth up to several hundred thousand euros. These often involve large sums of money, such as cash used to buy property or high value jewellery, where cash payments are sought.
Recent cases include a private individual who in December sold more than €60,000-worth of gold bars, and ended up with bundles of €200 notes marked ‘poker’. Similarly, in November, customs officers at the Franco-Italian Modane border discovered €1million in fake €200 notes, prompting the launch of an investigation.
And in March, near Mulhouse, a luxury watch dealer was given €80,000 in fake €500 notes marked ‘specimen’.
Mr Hippert said that the crooks often give the appearance of respectable business people, by holding meetings in the plush lounges of major hotels in Paris, the Côte d'Azur, Switzerland, Monaco, Hong Kong or Singapore.
Cash transactions may begin with genuine money in order to deceive the seller, while the rest of the cash will be fake. Some cash transactions reach as much as €1million, Mr Hippert said.
"[The scams are] all based on cunning and sleight of hand," Mr Hippert said. "By the time the victim realises the trick by opening the briefcase in their hotel room, the swindlers have disappeared."
It is unlikely that the discovery would be regularly reported, because "not all the goods would have been declared to the tax authorities" in the first place, the commissioner added.