German prosecutors have asked a court to permit the extradition of the former Catalan separatist leader Carles Puigdemont to Spain.

Prosecutors in the northern town of Schleswig announced on Tuesday morning they have requested Puigdemont to be put under arrest for extradition purposes after “intensive examination” of the European arrest warrant issued by Spain.

The former Catalan president has been detained at a prison in the town of Neumünster since he was picked up on 25 March, shortly after crossing over the Danish border into northern Germany.

Puigdemont had been living in self-imposed exile since Catalonia’s unilateral declaration of independence in October, but left the country last month to give a series of talks in Finland.

Spain is seeking the 55-year-old’s extradition under charges of misuse of public funds in relation to that declaration, as well as “rebellion” in organising an unauthorised referendum.

An extradition request requires that the conduct that gave rise to the arrest warrant in Spain would also be punishable under German criminal law. But while the charge of rebellion has not been part of the German criminal code since the 1960s, the state prosecutor said on on Tuesday it believed it could be equated with high treason in German law.

The Schleswig court is likely to take several days to decide whether to extradite Puigdemont, and could yet come to a different conclusion.

The Catalan separatist’s lawyers have filed an appeal and urged the German government to intervene in the case, citing its “political dimension”. The appeal states that the offence of rebellion, which under Spanish law can fetch up to 30 years in prison, was unjustified since there were only isolated instances of violence before the independence referendum on 1 October.

However, German media is reporting that Angela Merkel’s government has already decided not to veto any decision made by the judiciary.

“Spain is a democratic state where rule of law exists”, the chancellor’s spokesman, Steffen Seibert, said last week. “It remains the conviction of the German government that a solution to this Catalonia conflict has to be found within Spain’s legal and constitutional order”.