The courts thus overturn a ruling last week by the Central Electoral Board stipulating that Carles Puigdemont and two other separatist members of his regional executive should be excluded from the list for the European Parliament elections to be held on 26 May.
The Spanish Supreme Court ruled on Sunday that it was up to the courts of the Litigation-Administrative of Madrid to make the final decision on the appeal filed by the three fugitives investigated for their participation in the attempt to independence of Catalonia in October 2017.
Spanish courts have issued European arrest warrants against Carles Puigdemont, Antoni Comín and Clara Ponsatí.
The controversy around Puigdemont began when the Catalan Parliament unilaterally declared independence on October 27, 2017, which resulted in the Spanish government's suspension of Catalan autonomy.
On October 30 of that year, charges of rebellion and misuse of public funds against Puigdemont and against other members of the Catalan government were levied, leading them to flee to Belgium under arrest warrants from European authorities.
On 21 December 2017, in the regional elections, Puigdemont was re-elected to the Catalan parliament, but was prevented from taking office, maintaining his exile in Belgium, having been detained on a German motorway and then released on bail.
In July 2018, the Supreme Court suspended Puigdemont as deputy in the Catalan parliament.
In March of this year, Puigdemont announced that he would run for the European Parliament, as head of the list by Together for Catalonia, accompanied by his former collaborators Antoni Comín and Clara Ponsati.
The former regional vice-president, Oriol Junqueras, who was in Spain and was provisionally detained a year and a half ago, is the main accused of a group of 12 Catalan politicians in the ongoing trial on Catalonia's attempt to become independent.