A Franco-Iranian researcher with the prestigious Paris Institute of Political Studies has been arrested in Iran, the French Foreign Ministry said on July 15.
Paris called on Tehran to allow consular access to her without delay.
Fariba Adelkhah, an anthropologist and author of several books on Iran, was reportedly detained last month on unknown charges.
Unconfirmed reports suggested Iran’s powerful Islamic Revolutionary Guards Corps (IRGC) was behind her arrest on suspicion of spying.
"The French authorities in this difficult context have taken steps with the Iranian authorities to get information from them on her situation and the conditions of her arrest and asked for consular access," the ministry said in a statement.
"No satisfactory response has been given to these requests. France calls on the Iranian authorities to bring to light Mrs Adelkhah's situation and reiterates its requests, especially the authorization of consular access without delay," the statement added.
An Iranian government spokesman said on July 14 that he had heard reports about her arrest while suggesting that he did not have any further information.
Adelkhah’s arrest comes amid efforts by France to reduce tensions between Tehran and Washington over the 2015 nuclear deal, which the United States exited last year while re-imposing crippling sanctions.
In recent years, several Americans and dual nationals have been jailed in Iran on alleged espionage charges.
Iranian authorities have not provided any solid evidence to back their claims.
Among those jailed is Xiyue Wang, a Princeton University student who has been sentenced to 10 years in jail for espionage. He was arrested in August 2016 while conducting research for his dissertation on Iran's Qajar dynasty. Both Wang and the university deny the claims.