(CNN) Weather sensors at Paris-Charles de Gaulle Airport, France’s busiest airport, have been tampered with, leading the French Meteorological Association to suspect gambling fraud.
France’s national meteorological agency, Météo France, said in a statement to CNN on Thursday that it had filed a formal complaint regarding “tampering with the automatic data processing system” at Charles de Gaulle Airport, which is used to measure Paris’ daily temperatures.
Twice in April, users of American gambling platform Polymarket successfully bet on an unexpected rise in temperatures in the French capital, CNN affiliate BFMTV reported. Polymarket, launched in 2020, allows users to bet on future events, such as the highest temperature in a city on a given day.
According to BFM, temperature sensors at Charles de Gaulle Airport suddenly rose to 22 degrees Celsius (about 71.6 degrees Fahrenheit) on April 6 at around 7 p.m. local time (2 p.m. ET), before returning to cool spring temperatures.
The unusual temperature rise was reported by members of the French climate nonprofit Infoclimat, and at around 9:30 p.m. local time (4:30 p.m. ET), Meteor France recorded a temperature of 22 degrees Celsius in Paris, despite an average temperature of 18 degrees Celsius (64.4 degrees Fahrenheit) throughout the afternoon. A Polymarket user then successfully bet on 22°C and won $14,000.
The second unexpected spike occurred nine days later, on April 15, when the temperature recorded by Charles de Gaulle’s sensors once again reached 22 degrees, four degrees warmer than the previous day. This time, a user on the Polymarket site won $20,000 by betting on the 22°C figure.
Infoclimat said it had informed Météo France of the spike again, and some climate change enthusiasts on the association’s forums speculated that battery-powered hair dryers may have been used to tamper with the sensors, French newspaper Le Monde reported. The exact cause has not yet been confirmed.
In a statement sent to CNN, Meteor France said it had filed a complaint with airport police in Charles de Gaulle and an investigation is currently underway. Airport police declined CNN’s request for comment.
This is not the first time polymarket has been embroiled in controversy. An exclusive CNN investigation published in late March found evidence that a trader accurately predicted US and Israeli military action against Iran and made nearly $1 million in successful bets on Polymarket over two years, raising suspicions of insider trading.
CNN has reached out to Polymarket for comment.
