Israel said in June it would use any means necessary to prevent suspected Mossad agent Uri Brodsky from being extradited.
German prosecutors said Brodsky was arrested in Poland earlier this year in connection to using a fake German passport. He is believed to be the first Israeli spy allegedly tied to the slaying of Mahmoud al-Mabhouh in a Dubai hotel in January.
Mabhouh, a Palestinian national who founded the militant wing of Hamas, was discovered dead in a Dubai hotel in January. Dubai police said 12 British, six Irish, four French, three Australian and one German passports were connected to suspects in the Mabhouh assassination.
A court in Warsaw announced it was extraditing Brodsky to Germany on charges of forgery, not espionage.
Anna Mika-Kopec, Brodsky's legal counsel, said she had been given three days to file a formal appeal of the extradition, Israeli newspaper Haaretz reports.
Berlin officials said the Israeli spy agency Mossad obtained a German passport linked by Interpol to the Dubai assassination by fabricating a story of Nazi persecution.