The suspect known as Uri Brodsky was handed over to German police at Warsaw’s international airport, police spokesman Mariusz Sokolowski said.
An Associated Press photographer saw a man at the airport wearing a hooded jacket pulled over his face to hide his identity as he was escorted by masked anti-terror police.
Brodsky appeared that way during several appearances at courts in Warsaw.
German prosecutors accuse him of illegally helping to procure a passport used in connection with the Jan. 19 slaying of Hamas commander Mahmoud Al-Mabhouh at a hotel in Dubai.
Prosecutors in Cologne, who are handling the case against Brodsky, were not immediately available for comment. But a German official who declined to be named due to the sensitivity of the issue said Brodsky was to arrive with a police helicopter at Cologne-Bonn airport in the afternoon.
Brodsky is expected to appear Friday morning before a judge, who will read out the warrant against him and decide at a closed-doors appearance whether Brodsky must remain in custody pending the filing of formal charges and a possible trial.
Brodsky was arrested June 4 at Warsaw airport on a European arrest warrant issued by Germany, which accused him of espionage and helping to falsely obtain a German passport.
However, Brodsky will not face spying charges in Germany. The Polish court that granted the extradition request said he could only be sent to face prosecution for his alleged involvement in faking an identity.
Israel’s suspected forgery of European passports allegedly used by members of a hit squad who took part in the killing of the Hamas leader in Dubai in January annoyed several European countries, including Britain, which expelled an Israeli diplomat over the matter in March.