Briere, 36, has been held in Iran since May 2020, when he was arrested after flying a helicam - a remote-controlled mini helicopter used to obtain aerial or motion images - in the desert near the Turkmenistan-Iran border.
Briere was charged with spying and "propaganda against the Islamic Republic". He had through his lawyers consistently denied wrongdoing.
Neither Briere's lawyer in France nor Iran's judiciary were immediately available for comment. There was no immediate reaction by France's foreign ministry.
In recent years, Iran's elite Revolutionary Guards have arrested dozens of dual nationals and foreigners, mostly on charges related to espionage and security.
Briere's trial came as the United States and parties to Iran's 2015 nuclear deal, including France, tried to revive the pact after then-US President Donald Trump pulled his country out of the agreement in 2018.
Rights groups have accused Iran of trying to extract concessions from other countries through such arrests. Western powers have long demanded that Tehran free their citizens, whom they say are political prisoners.
Earlier this month, Iran re-imprisoned Franco-Iranian academic Fariba Adelkhah, sentenced to five years in jail in 2020 but recently living under house arrest. France has demanded Adelkhah's immediate release.