
Logging in the Białowieża Forest began in May 2016, but the European Commission took Poland to court last year, arguing that it was destroying a forest that boasts unique plant and animal life.
“The forest management operations concerning the Puszcza Białowieska Natura 2000 site that have been undertaken by Poland infringe EU law,” the European Court of Justice said in a statement.
It said that the Polish government must comply with the court ruling to stop logging “without delay” or face financial penalties.
Białowieża, which straddles the border with Belarus, includes one of the largest surviving parts of the primeval forest that covered the European plain 10,000 years ago.