French authorities launched an investigation after temperature spikes at Paris Charles de Gaulle Airport coincided with unusual betting activity on Polymarket. The national meteorological service Météo-France filed a complaint after sensors recorded sudden jumps from 64°F to 70°F and later from 61°F to 72°F, raising suspicions of tampering.

The unusual temperature swings came as $1.4 million was wagered on Polymarket, significantly higher than typical daily activity. Weather data at airports is crucial for safety calculations affecting takeoff distance and aircraft treatment, making potential tampering particularly dangerous for air travel operations.

This incident follows other controversial betting cases on prediction markets, including a U.S. Army soldier charged with using classified information for political wagers. In response, Polymarket switched to using temperature readings from a different Paris airport, highlighting the growing risks as financial markets expand into new data domains.