Paris (AFP) - When French researcher Roland Marchal was thrown into prison in Iran back in June 2019, he was convinced it was all a mistake and that he would be released shortly.
But as days turned into months and his hopes of being freed were repeatedly dashed, hope itself became painful.
"You become afraid of hope because you keep faith despite all the evidence that you will be there for a long time. You always have hope, and, obviously, it hurts a lot," he told AFP in an interview back home in France days after his release following a nine-month ordeal.
Marchal and his partner, fellow researcher Fariba Adelkhah, 60, were detained on accusations of plotting against national security.
The pair, who work at the prestigious Sciences Po university in Paris, have denied the charges.
Abdelkhah, who was born in Tehran, remains in jail, but Marchal was freed by Iran on March 20 after France released an Iranian prisoner threatened with extradition to the United States.
"I was never tortured, I was fed properly, I had access to a doctor," Marchal said.
But stress, anguish and isolation led to a deterioration in the expert's health.
"I had nothing left. I had my clothes and a towel, and I had access to a toilet in my cell, which was a luxury. But I didn't have access to anything else."
Books were sparse and phone calls to Marchal's family forbidden, in contrast to other detainees who were allowed one or two calls a week.
- 'Very hard, very long' -
But the hardest part was the beginning, Marchal said. Arrested at the airport upon arrival in Iran's capital Tehran, the researcher was interrogated for "four, five, six hours" before being taken to Evin prison.
"I had to leave my normal clothing, put on prison clothes and I found myself in a cell," the researcher said.
"I didn't understand what they wanted.
"When I found out Fariba was also imprisoned, I told myself that it was going to be very hard, very long."
Unlike Abdelkhah who is an expert on Iran, Marchal's research focuses on sub-Saharan Africa. But the elite Revolutionary Guards, which answers to the supreme leader, accused the academic of secretly working on Iran.
By February, coronavirus had started to spread in the country.
But Marchal wasn't afraid of being infected. "I was afraid of being locked up, isolated, of not having any books. Those were my fears," he said.
When Marchal arrived in Paris on March 21, he found the city under lockdown as France struggled to contain COVID-19 which has caused over 10,000 deaths on its soil.
Although like all French residents Marchal is only allowed out for specific motives, the restrictions are nothing compared to his experience in jail.
"Here I can call my family, look out the window of my apartment, I can see sunlight," he said.
Back in France, Marchal will continue to seek the liberation of Abdelkhah. She has both French and Iranian citizenship, but Tehran does not recognise dual nationality.
"It's going to be long," he said. "But this time we must not lose hope."