French authorities have launched an investigation after someone won $34,000 on a weather-related bet amid allegations that a temperature sensor at Paris’s Charles de Gaulle Airport may have been tampered with.
Temperature readings at the airport surged on two occasions in April, coinciding with the timing of high-stakes bets that led to significant payouts on Polymarket, the world’s largest prediction market.
On April 6 and April 15, unusually high peak temperatures were recorded that were well above forecasts. Reports indicated readings of 21°C at 7pm and 22°C at 9:30pm respectively.
The probability of temperatures exceeding 18°C on both evenings had been estimated at just 1%, meaning those who placed bets on this unlikely outcome would have received substantial payouts.
Some crypto news sources and trading publications have suggested that a hairdryer may have been used to artificially inflate the temperature readings, although these claims remain unverified.
A Météo-France spokesperson stated: “In view of physical findings on one of our instruments and the analysis of sensor data, Météo-France was indeed led to file a complaint for alteration of the operation of an automated data processing system with the Air Transport Gendarmerie Brigade of Roissy.
“As the investigation is ongoing, we do not wish to make any further comments in order to ensure the proper conduct of the procedure.”
Criticism of Polymarket and related bets is mounting. In Europe, regulators have taken a strict stance towards prediction markets, with a number of EU authorities ordering operators such as Polymarket to cease trading in their jurisdictions.
Meanwhile, in the US the Wisconsin Department of Justice has filed lawsuits this week against Kalshi, Robinhood, Coinbase, Polymarket, Crypto.com and affiliated entities, seeking to stop the companies from offering sports-related event contracts to customers in Wisconsin.
Furthermore, US Army soldier Gannon Ken Van Dyke has recently been charged over alleged Polymarket trading linked to classified information.
Earlier this month, Polymarket was also criticised after taking bets on the fates of US pilots shot down in Iran.
The operator has also drawn suspicion over potential insider trading following bets linked to US military action in Venezuela in January.
Italian FC Lazio recently announced a multi-year partnership with Polymarket, which will become the club’s main sponsor as well as its official fan intelligence and digital insights partner
