In the same year, the artist Valtonyc was convicted of the same crime.
But when his sentence was to be upheld in 2018, he fled from Spain to Belgium where he has lived in exile ever since.
Spain wants Belgium extradited and a court will rule on 23 November.
But already on October 28, a Belgian court ruled that Valtonyc had not committed a crime against the crown under Belgian law.
Represented by Puigdemont's lawyers
In September 2020, Belgium's decision on extradition was delayed because the country has a law from 1847 that prohibits insults to the king.
But the court now considers that the Belgian royal laws are incompatible with the country's and freedom of expression laws, reports El País.
This means that the probability that Valtonyc will be released decreases, the newspaper writes.
Former Catalan regional leader Carles Puigdemont also went into exile in Belgium after being accused by the Spanish state of insurrection and incitement in connection with Catalonia's independence attempt four years ago.
Valtonyc and Puigdemont are represented by the same lawyers.