A French tourist detained in Iran ten months ago is facing two charges of "spying and propaganda against the system", according to his lawyer.
Benjamin Briere, 35, was arrested after flying a drone near the Iran-Turkmenistan border.
His lawyer Saeid Dehghan said Mr Briere could face a long prison sentence if found guilty.
It comes at a time of rising tensions between Iran and European countries and the US over Iran's nuclear capacity.
Mr Briere is being held in a prison in the city of Mashhad and is in good health, Mr Dehghan said, adding that "his spying charges [are] because of taking pictures in forbidden areas".
The charge of "propaganda against the system", the lawyer said, was the result of a social media post by Mr Briere that said "the hijab is mandatory" in Iran but not in other Islamic countries.
"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," Mr Dehghan added.
In a Twitter post outlining the charges on Monday, the lawyer included a photo of Mr Briere.
Last month, France's foreign ministry confirmed a French citizen was being held in Iran and that it was monitoring the situation.
It has not commented on the charges.
France is part of a group of countries - along with the US, UK, China, Russia and Germany - that say they are trying to restore a nuclear deal that was struck with Iran in 2015 but was abandoned by US President Donald Trump in 2018.
The Trump administration then reinstated sanctions that Iran has said must be lifted before it will agree to restore the pact.
Iran has insisted that its nuclear programme is peaceful, but suspicions by other nations, including France, that it may be being used as a cover for building a nuclear bomb led to sanctions being imposed in 2010.
Human rights activists in the past have accused Iran of detaining foreign or dual-nationality citizens to use as leverage against other countries.
The charges against Mr Briere come after British-Iranian Nazanin Zaghari-Ratcliffe appeared in court in Tehran on propaganda charges. The charity worker has already served five years in prison in Iran.
