Carles Puigdemont is wanted in Spain over his involvement in the Catalan independence referendum
The former Catalan President Carles Puigdemont has been detained in Germany.
German police intercepted Mr Puigdemont at the Danish border.
The politician has been in self-imposed exile following the Catalan independence referendum last year.
Mr Puigdemont is wanted by Spain on charges of "rebellion" and "sedition" over his involvement in the vote.
His lawyer, Jaume Alonso-Cuevillas, said he was attempting to return to Belgium.
A German police spokesman said Mr Puigdemont "was arrested today at 11:19 am by Schleswig-Holstein's highway patrol force."
He said the detention was based on a European warrant, adding he is “now in police custody."
His lawyer said on Saturday that the former president had slipped out of Finland. He had been in the country since Thursday for talks with MPs.
A Spanish Supreme Court judge reactivated an international arrest warrant for Mr Puigdemont on Friday.
Finland's National Bureau of Investigation (NBI) confirmed on Saturday that it had received a European arrest warrant for "a Spanish citizen visiting Finland."
The NBI said they were unaware of the person's location.
"The president was going to Belgium to put himself, as always, at the disposal of Belgian justice," Joan Maria Pique, Puigdemont's spokesman said.
The Catalan parliament declared unilateral independence in October 2017.
Spain's government then sacked Mr Puigdemont and his entire administration before dissolving the parliament.
Catalonia has been under direct rule from Madrid since the end of October.
Mr Puigdemont fled to Belgium hours before Spain's attorney general asked for charges to be brought against him and other members of his cabinet.
The crime of rebellion carries a maximum sentence of 30 years' imprisonment, while sedition carries a 15-year penalty.