Thousands of undeclared swimming pools have been discovered in France thanks to a new artificial intelligence system.
The French taxman has now raked in millions of euros from homeowners who failed to report the facilities.
New AI software by Google and Capgemini is able to spot pools using aerial imagery which is then cross-checked with land registry databases.
During a trial run last year looking at nine French regions the software detected more than 20,000 pools, which led to the collection of some 10 million euros in tax revenue.
Since pools boost property values they usually lead to higher property and residency taxes.
Private pool sales had already been surging in France before the Covid pandemic, which saw a boom in installations as millions of employees began working from home more often.
The tax office says it is now looking at using the system to spot undeclared annexes, extensions and verandas including permanent pergolas.
“We are particularly targeting house extensions like verandas, but we have to be sure that the software can find buildings with a large footprint and not the dog kennel or the children’s playhouse,” Antoine Magnant, the deputy director general of public finances, told Le Parisien newspaper.
In April it was claimed the Google-Capgemini software had a 30% margin of error.
It mistook solar panels for swimming pools and failed to pick up taxable extensions hidden under trees or in the shadows of a property.
“This is our second stage of research and will also allow us to verify if a property is empty and should no longer be taxed,” Magnant added.