A 39-year-old Syrian national facing terrorism-related charges has been jailed in Germany, but he was found guilty of attempted fraud instead in a surprise ruling.

Prosecutors had accused the defendant of "attempted homicide involvement" and were seeking a 10-year prison term on the assumption that he had been planning a terrorist attack.

However, the man was sentenced to two and a half years in prison after the court in Saarbruecken on Germany's western border with France found that he was in fact using the plot as a ruse to extort money from Daesh.

The defendant had sought contact with the terrorist militia via internet chats, leading authorities to believe that he was trying to secure financial means and support for an attack in Germany or neighboring countries.

However, there was no evidence of a concrete plan and police found no explosives when he was arrested on December 31.

"The defendant was neither capable of nor willing to execute the planned attacks," presiding judge Bernd Wagner said.

The man's defense lawyer, who had demanded his client's acquittal, has requested an appeal.