An Iranian appeals court has upheld an eight-year prison sentence against a Frenchman convicted on spying charges, his Paris-based lawyer said Tuesday.
Benjamin Briere was arrested in May 2020 after taking pictures in a national park with a recreational drone. His lawyers and family have accused Iran of holding him as a "hostage".
The lawyer, Philippe Valent, said Briere's case was being "instrumentalised" by the Iranian authorities.
"It's shocking and dramatic," he told AFP, adding that the verdict coincided with the resumption of negotiations between Tehran and Western powers on Iran's nuclear programme.
"This trial is a masquerade -- the submerged part of a huge issue that is beyond us," Briere's sister, Blandine, told AFP.
The appeals court explained its decision by accusing Briere of being "an agent in the service of an enemy state" in its verdict, which was translated by Briere's Iranian lawyer, Valent said.
Briere, 36, who was convicted in January for spying and propaganda against Iran's Islamic system, had appealed the sentence.
His lawyer said he had not even been given access to the full indictment against him.
The verdict against Briere comes as Iran and world powers are seeking to reach agreement at talks in Vienna on reviving the 2015 deal over the Iranian nuclear programme.
Chief negotiators from the United States and Iran were due to start indirect talks in Qatar on Tuesday, to try to remove obstacles stalling attempts to revive a landmark nuclear deal.
Nationals of all three European powers involved in the talks on the Iranian nuclear programme -- Britain, France and Germany -- are among foreigners being held in Iran.
"We ask the French, American and British authorities to make the liberation of hostages a pre-condition for the resumption of negotiations," Valent said.
During his original trial, Briere's sister Blandine told AFP her brother was a "political hostage" subjected to a "parody of justice".
"It is a political trial, and it is useful to Iran, which is sending a message to the French government," she said.
The French foreign ministry at the time described the verdict as "unacceptable", saying Briere was a "tourist".
Three other French nationals are also being held in Iran.
Franco-Iranian researcher Fariba Adelkhah was jailed for five years in May 2020 on a national security charge.
Two other French nationals were arrested in May, accused by Iran of having entered the country with the aim of destabilising.
Paris has denounced that claim as groundless.
Iran insists all the foreigners held are tried in line with domestic law but has repeatedly expressed its readiness to carry out prisoner swaps.