A battery‑powered hairdryer allegedly altered a temperature sensor near Charles de Gaulle’s runway, tipping Polymarket’s Paris weather bets and netting an anonymous user $34,000.

French authorities found two unexpected temperature spikes over the past month, each time a gambler capitalized on the low‑probability odds posted on Polymarket. The site’s reliance on a public‑road sensor made the tampering feasible.

Météo‑France filed a complaint after detecting the anomaly, and the sensor has since been relocated. Although Polymarket has not reclaimed the winnings, the incident exposes the vulnerability of real‑world data feeds in prediction markets.

The episode underscores the need for tighter safeguards on open‑access sensors, especially as platforms like Polymarket expand into high‑stakes, real‑time events.