The French government has collected nearly $10 million in additional taxes after using machine learning to spot undeclared swimming pools in aerial photos. In France, housing taxes are calculated based on a property’s rental value, so homeowners who don’t declare swimming pools are potentially avoiding hundreds of euros in additional payments. From a report: The project to spot the undeclared pools began last October, with IT firm Capgemini working with Google to analyze publicly available aerial photos taken by France’s National Institute of Geographic and Forest Information. Software was developed to identify pools, with this information then cross-referenced with national tax and property registries. The project is somewhat limited in scope, and has so far analyzed photos covering only nine of France’s 96 metropolitan departments. But even in these areas, officials discovered 20,356 undeclared pools, according to an announcement this week from France’s tax office, the General Directorate of Public Finance (DGFiP), first reported by Le Parisien.