In a statement issued in Montreal, Denis McCready said Solouki went on trial in Tehran on November 17 and was questioned by a judge before the three-hour hearing was adjourned indefinitely.
Solouki, who has Canadian residency, is accused of intent to commit propaganda against the Iranian government.
She was arrested on February 27, after returning to Iran to make a film documentary about burial customs among Iranian minorities.
She came to the attention of the authorities after displaying an interest in a mass grave outside Tehran that contained the remains of people summarily executed by the government in 1988.
McCready, a friend of Solouki's, says Iran has the opportunity to close this case, which he calls a minor incident inflated for no apparent reason. He says that "Iran's government has the opportunity to make a tangible gesture and allow her to leave Iran."
He notes that Solouki "is not a powerful political dissident" but simply "an independent filmmaker and doctoral student who wants to go back to France."
Solouki spent a month in the notorious Evin prison before being released on bail. But her passport remains confiscated and she has not been permitted to leave the country.
McCready says Solouki urgently needs to go to France to receive proper medical treatment for a wound to her cheek that she suffered when hit by a motorcycle in July. The wound has required four operations, and is still swollen.
The media rights group Reporters Without Borders has also taken up Solouki's case, calling on authorities earlier this year to let her leave Iran.