Mostafa Azizi, 52, had been a permanent resident in Canada for several years before deciding to return to Iran in January.
Soon after he arrived, Azizi was arrested. He is being held in Tehran's Evin prison.
Azizi has been charged with insulting Iran’s supreme leader and spreading propaganda against the Islamic establishment.
His son Arash told CBC News that the specific allegations against his father are unclear, but he said they appear to do with things Azizi posted to social media.
His father was put in solitary confinement for more than two weeks, but his son said Azizi is now in the general population.
Azizi awaits a trial scheduled to take place in June.