President Emmanuel Macron has demanded that Franco-Iranian academic Fariba Adelkhah, whom Tehran has sentenced to six years in prison, be released immediately.
"One year ago, Farida Adelkhah was arbitrarily arrested in Iran. It is unacceptable that she is still in prison," Macron tweeted on June 5.
"My message to Iranian authorities: justice demands that our compatriot be immediately released," Macron said in his tweet marking the one-year anniversary of Adelkhah’s arrest.
Adelkhah, 60, was sentenced in May to six years in prison on charges relating to security.
Iranian officials said last year that Adelkhah, a prominent anthropologist who often traveled to Iran for research, had been arrested on espionage charges.
In March, a prisoner exchange was carried out between Iran and France, swapping researcher Roland Marchal for engineer Jalal Ruhollahnejad. But there has been little indication that Adelkhah will be released in a similar manner.
Iran has rejected previous calls to release Adelkhah calling the demands amounted to interference in Tehran's internal affairs.
Iran does not recognize dual nationality.
"This ongoing situation can only have a negative impact on the bilateral relations between France and Iran, and can only significantly reduce the trust between our two countries," Foreign Minister Jean-Yves Le Drian said in a statement on June 4.
Relations between France and Iran remain tense over Iran's nuclear activities, its ballistic missile program, and regional influence.