Friends and former colleagues of a jailed Canadian-Iranian academic say they're still having trouble believing she's behind bars in Iran.

Many of them gathered at a rally in Montreal today to call for Homa Hoodfar to be freed.

Hoodfar, 65, has been held at Tehran's notorious Evin prison since June 6 on what her friends and family describe as trumped-up charges.

Her family has said the Iranian probe into the retired anthropology professor centred on her "dabbling in feminism" and security matters.

Former colleagues and students at Montreal's Concordia University say she's a sweet and generous person with no political leanings.

Nearly 5,000 academics worldwide have signed a petition this summer in support of Hoodfar.