French citizen Benjamin Briere is  facing charges of espionage and propaganda following his arrest 10 months ago, his lawyer said on Monday.

"On Sunday, March 15, he was charged with two counts of espionage and propaganda against the Islamic Republic," said Briere's lawyer Saeid Dehghan told Reuters, adding that Briere faces a long-term jail sentence.

Dehghan confirmed the case in a tweet, saying that the 35-year-old had been charged with spying after taking photos of "forbidden areas."

Briere was arrested after flying a helicam in the desert near the Turkmenistan-Iran border.

What are the charges?

The French tourist's Iranian lawyer explained in his tweet that: "Benjamin Briere's final defense against the charges of espionage and propaganda against the state have been taken."

"The basis for the charge of espionage: Taking photographs of forbidden areas!"

"The basis for the charge of propaganda: Posing the question on social media of why the hijab is "mandatory" in the Islamic Republic, but "optional" in other Muslim countries," Dehghan said.

"My colleagues and I believe that these charges are false and baseless, but we have to wait for the judge to conduct a full investigation in the next few days and announce his verdict," Dehghan told Reuters.

"He is in Vakilabad prison in the city of Mashhad. His health is good and he has access to his lawyers and he benefits from consular protection and the French embassy officials have been in regular contact with him," Dehghan added.

Observers say the fate of Briere could be linked to that of Assadollah Assadi, an Iranian diplomat who was sentenced last month by a Belgian court.

He was given 20 years in prison for having planned an attack on a gathering of an Iranian opposition group in France.

The Belgian judiciary announced on March 8 that Assadi had appealed his conviction.

Why is Iran arresting foreigners?

Iran's Revolutionary Guard has arrested dozens of dual nationals and foreigners in recent years as tensions between the Islamic Republic and the US, under the Trump administration, came to a head.

Human rights activists accuse the Iranian government of using the arrests to gain leverage in political negotiations with western countries. Tehran has denied the allegations.

US President Joe Biden has shown a keenness to return to the Iran nuclear deal (JCPOA) after Donald Trump pulled the country out of the agreement. Iran, already spurned by the US, has demanded the lifting of sanctions imposed by Trump before coming to the table.

France is also a member of the nuclear deal and has shown consistent support for its continuation.

Report by DW staff and Reuters