France, May 7 -- Locked in a windowless cell with the lights on day and night, French teacher Cecile Kohler and her partner Jacques Paris on Wednesday markedthree years in Iran's notorious Evin Prison. As the anniversary passes, Kohler's sister has told RFI their situation is unbearable and deteriorating fast.

"They are at the end of their strength. Jacques's face is more and more marked by the detention - you can feel he is dying slowly in that cell," Noemie Kohler told RFI. "Cecile and Jacques are increasingly desperate and are less and less optimistic."

Kohler, 40, and Paris, who is in his seventies, were arrested on 7 May 2022 at the end of a tourist trip to Iran. They are accused of spying - charges they strongly deny.

They are be...