The Belgian painter Luc Tuymans has been found guilty of plagiarism by a court in Antwerp. The case relates to Tuymans’ 2011 painting, A Belgian Politician, which is based on a 2010 photograph of the right-wing Belgian politician Jean-Marie Dedecker by the photographer Katrijn Van Giel.

The US art site Hyperallergic reports that Tuymans, who accepted that he used the photo as inspiration, defended his use of the image on the basis that it was parody and therefore exempt from EU copyright law.

The court disagreed, imposing a fine of 500,000 euros (£384,000) if Tuymans either shows the original painting – which was bought by an American collector – or creates any more ‘reproductions’ of Van Giel’s work.

Tuymans’ lawyer, Michael De Vroey, said: “Luc Tuymans wanted to create a strong image to deliver a critique of the move to the right wing in Belgian society. His work is therefore more than just a painted version of a photo. The format and colour contrasts are different, so that no confusion could be possible.”

Tuymans has used photographs as source material for his paintings throughout his career, perhaps most famously in his 2005 painting, The Secretary of State, of former US secretary of state Condoleezza Rice.

Following the ruling, De Vroey said: “Like many contemporary artists, the work of Luc Tuymans is based on existing images. How can an artist call the world into question with his works if he isn’t allowed to use that world’s images?”

Writing about the court’s decision in The Guardian, art critic Adrian Searle said: ‘The painting A Belgian Politician is not a reproduction. Comparing Van Giel’s photograph and a reproduction of Tuymans’ painting levels out the conspicuous fact that paintings and photographs are different kinds of objects, that we read in different ways.’

Tuymans, who next week opens a show at David Zwirner’s London gallery, plans to appeal against the decision.