The discovery of thousands of undeclared private swimming pools in France has provided an unexpected windfall for French tax authorities. Following an experiment using artificial intelligence (AI), more than 20,000 hidden pools were discovered. They have amassed some €10m ($9.9; £8.5m) in revenue, French media is reporting. Pools can lead to higher property taxes because they boost property value, and must be declared under French law. The software, developed by Google and French consulting firm Capgemini, spotted the pools on aerial images of nine French regions during a trial in October 2021.

France experienced its worst drought on record last month, and officials have since been cracking down on conserving water. Now a new artificial intelligence (AI) technology could be added to their arsenal, after it successfully uncovered 20,356 illegally-built private swimming pools. The country's tax authority announced yesterday that the system allowed it to collect about €10 million (£8.5 million) from homeowners who failed to report the facilities. Developed by Google and Capgemini, the AI software was trained to spot pools in aerial images of nine French departments. The results of a trial run last October were then cross-checked with land registry databases, before Direction generale des Finances Publiques (DGFiP) took action.

French tax authorities using AI software have found thousands of undeclared private swimming pools, landing the owners with bills totalling about €10m. The system, developed by Google and Capgemini, can identify pools on aerial images and cross-checks them with land registry databases. Launched as an experiment a year ago in nine French departments, it has uncovered 20,356 pools, the tax office said on Monday, and will be extended across the country. Modifications to property, including adding swimming pools, must be declared to the tax office within 90 days of completion. As property taxes are based on the rental value of the property, improvements mean an increase in taxes.