France probes weather sensor tampering tied to Polymarket bets

Thursday 23 April 2026 - 17:20

By: Dakir Madiha

France probes weather sensor tampering tied to Polymarket bets

French authorities have opened a criminal investigation into suspected manipulation of a weather sensor at Paris Charles de Gaulle Airport after unexplained temperature spikes coincided with profitable bets on Polymarket. The incidents, recorded earlier this month, generated roughly 34,000 dollars in winnings for at least one trader, raising concerns about potential exploitation of physical data inputs used in cryptocurrency-based prediction markets.

Météo-France filed a complaint with the air transport gendarmerie over alleged interference with an automated data processing system. The complaint focuses on readings from April 6 and April 15. On the first date, the sensor registered a rapid increase of about four degrees Celsius within 12 minutes, briefly reaching 22.5 degrees before returning to normal levels. A similar anomaly occurred on April 15, when temperatures jumped from around 18 to 22 degrees late in the evening. Nearby weather stations did not record comparable fluctuations during either event.

Meteorologists have indicated that such abrupt variations are unlikely under normal atmospheric conditions. Experts pointed to the possibility of physical interference, such as the use of a heating device placed near the sensor, as the most plausible explanation. The absence of corroborating data from surrounding stations has reinforced suspicions that the readings were artificially influenced.

Blockchain analysis has added to the concerns. Contracts on Polymarket tied to Paris temperatures settle based on the maximum daily reading recorded at the designated airport station. On April 6, a brief spike above 21 degrees triggered a payout exceeding 14,000 dollars to a recently created account. A second spike on April 15 resulted in an additional payout of about 20,000 dollars. Analytics firm Bubblemaps reported that a trader placed a timely position shortly before the second spike, achieving what it described as a 180-fold return.

The sequence of transactions and the use of newly created accounts have intensified suspicions of coordinated manipulation. The case highlights vulnerabilities in prediction markets that rely on single data sources, a known issue often described as the oracle problem within cryptocurrency systems.

Following the incidents, Polymarket quietly changed its temperature data source for Paris from Charles de Gaulle Airport to Le Bourget Airport. The platform did not issue a public statement and did not reverse the payouts linked to the disputed events. Critics argue that switching sensors does not address the underlying risk, as the system still depends on a single external data feed.

Under French law, interfering with an automated data processing system can carry penalties of up to seven years in prison and a fine of 300,000 euros. The investigation now seeks to determine whether the anomalies resulted from deliberate tampering and whether financial gain from prediction markets played a direct role.