On Friday, Persian New Year's Day, Iran announced an exchange of detainees between Paris and Tehran.
French researcher Roland Marchal was released from jail in Tehran as part of an apparent prisoner swap and flying home Saturday, French President Emmanuel Macron said.
Macron said in a statement he was “pleased” by the release of Roland Marchal, held by Iran for more than nine months on charges of violating state security laws.
France is also pushing for the release of a second French national detained in Iran, Marchal’s companion and researcher Fariba Adelkhah.
French President Emmanuel Macron "urged the Iranian authorities to immediately release our compatriot Fariba Adelkhah", AFP reported.
Marchal was originally arrested in June and charged with "spreading propaganda" after he went to Iran to visit Adelkhah, who is Franco-Iranian and often traveled to Iran for research on post-revolutionary Iranian society.
Adelkhah had been arrested on espionage charges, and though those charges were later dropped, security-related charges remain against her.
Both were researchers at the Center for International Research (CERI) at Sciences Po Paris and arrested in June 2019 at Tehran's airport.
Marchal was turned over to the French Embassy in Tehran, Iranian state TV said late Friday, hours after French authorities released Jalal Ruhollahnejad, an Iranian held in France.
French authorities did not comment on the case of Ruhollahnejad.
In Paris, their support committee has always claimed their innocence and demanded their immediate release, fearing for their lives.
"We welcome with relief the arrival of Roland Marchal in Paris after almost nine months of arbitrary detention in very harsh conditions" Professor Jean-François Bayart, a member of Marchal and Adelkah's commitee, told AFP. "But we're only half way there," he added.
Their concerns had increased due to the accelerated spread of COVID-19 in Iran, one of the most affected countries in the world with a death toll of 1,556 on Saturday.
The epidemic is particularly feared in the prison environment.
In recent months, Iran has exchanged prisoners with countries holding Iranian nationals who have been sentenced, awaiting trial, or are threatened with extradition to the United States.
Tehran also released several iconic prisoners on the occasion of Nowruz (Persian New Year) while Iran is still weakened by the pandemic.
Among them are Iranian-British Nazanin Zaghari-Ratcliffe, an employee of the Thomson Reuters Foundation, who obtained temporary permission to leave prison on Tuesday.