Briere, 36, has been detained in Iran since May 2020. He was apprehended while flying a helicam, which is a remote-controlled tiny helicopter designed to acquire aerial or motion photographs, in the desert near the Turkmenistan-Iran border.
"It is unacceptable that Benjamin Briere remains a hostage to negotiations on the part of a regime that persists in its desire to arbitrarily detain a French citizen and use him as a bargaining chip," Briere’s lawyer Philippe Valent said in a statement.
Briere, who has constantly denied the accusations, was sentenced to a further eight months in prison for "propaganda against the Islamic Republic," according to Valent.
His family is concerned about his physical and psychological state, according to Valent, who has urged French authorities to intervene.
One of Briere's Iranian lawyers, Saeid Dehghan, said Briere will appeal the verdict. He stated that his client was taken aback by the sentence, which was heavier than expected and included an additional allegation of assisting with opposing countries against Iran.
"His sentence is based on a different legal clause than the earlier one ... He has been convicted of cooperation with hostile states against Iran which carries a longer sentence than his previous one," Dehghan explained.
France's foreign ministry called the ruling "unsatisfactory," adding that it was in frequent communication with Briere.