A farmer in Belgium inadvertently changed geography by moving his country’s border with France. The farmer was driving a tractor and apparently got annoyed by a large stone blocking his path, BBC News reports. So, he slightly moved it.

Another person recently walking in the forest noticed the stone had been moved. The history enthusiast knew it wasn’t just any stone — it was there to mark the boundary between the two countries.

The marker had moved about 7.5 feet, according BBC News, affectively giving Belgium more land. 

“He made Belgium bigger and France smaller, it’s not a good idea,” David Lavaux, mayor of the Belgian village of Erquelinnes, told French TV channel TF1. 

The move could caused a problem for private landowners – and neighboring countries, Lavaux said. But people in both Belgium and France had a good laugh over it. 

“I was happy, my town was bigger,” the mayor said, laughing. “But the mayor of Bousignies-sur-Roc didn’t agree.”

The mayor of a neighboring French village told La Voix du Nord “we should be able to avoid a new border war,” BBC News reports. 

France and Belgium share a 390-mile border, which was established under a 1820 treaty signed after Napoleon’s defeat at Waterloo five years earlier.

The stones were placed when the border was first decided in 1819. 

Belgian authorities plan on simply contacting the farmer and asking him to return the stone – but if he doesn’t, the Belgian foreign ministry could open a Franco-Belgian border commission, something that hasn’t happened since 1930, according to BBC News. The farmer could also face criminal charges if he doesn’t comply.

“If he shows good will, he won’t have a problem, we will settle this issue amicably,” Lavaux told Belgian news website Sudinfo.