French authorities have opened an investigation into potential data manipulation after a series of suspicious wagers on Paris weather netted traders over $35,000 on the crypto prediction market Polymarket.
"Based on physical findings regarding one of our instruments and an analysis of sensor data, Météo-France has indeed filed a complaint with the Roissy Air Transport Gendarmerie Brigade regarding the tampering with an automated data processing system,” the French national weather service confirmed in a statement.
The complaint follows two separate incidents. On April 6, a Polymarket account named “Hoaqin” won nearly $14,000 after a temperature gauge at Charles de Gaulle Airport briefly spiked to 21 degrees Celsius. Nine days later, on April 15, another user, “xX25Xx,” profited by more than $21,000 from a $120 bet when the same sensor reported an evening jump to 22 degrees Celsius. Blockchain analytics firm Bubblemaps noted the second bet was 20 times larger than the trader's typical wager.
The incident highlights the growing risk of market manipulation on prediction platforms, which are facing increased regulatory pressure. Meteorologists have suggested the Paris temperature anomalies, which were not recorded by any other nearby stations, could have been caused by a simple portable heat source like a hairdryer held close to the sensor. Polymarket, which has not commented on the investigation, has since switched its data source for Paris weather markets to a different airport.
The Paris weather bets are the latest in a series of high-profile incidents to cast a shadow over the burgeoning prediction market industry. These platforms, including Polymarket and its U.S.-regulated rival Kalshi, have seen a surge in popularity, allowing users to bet on a wide range of real-world events.
However, their growth has been accompanied by repeated allegations of insider trading and manipulation. In January, a U.S. special operations soldier was accused of using classified information to win over $400,000 on Polymarket by betting on the capture of a Venezuelan political figure. In response to mounting pressure, Polymarket recently updated its rules to explicitly prohibit users from betting on events where they may possess confidential information or can influence the outcome.
This article is for informational purposes only and does not constitute investment advice.
