The initial spark for the 2017 protests was a sudden jump in food prices. Many believe that hard-line opponents of Iranian President Hassan Rouhani instigated the first demonstrations in the conservative city of Mashhad in northeastern Iran, trying to direct public anger at the president. But as protests spread from town to town, the backlash turned against the entire ruling class.
Soon, cries directly challenging Rouhani and even Supreme Leader Ayatollah Ali Khamenei could be heard in online videos shared by Zam. Zam's channel also shared times and organisational details for the protests.
Telegram shut down the channel over Iranian government complaints it spread information about how to make gasoline bombs. The channel later continued under a different name. Zam, who has said he fled Iran after being falsely accused of working with foreign intelligence services, denied inciting violence on Telegram at the time.
The 2017 protests reportedly saw some 5000 people detained and 25 killed.
The details of his arrest still remain unclear. Though he was based in Paris, Zam somehow returned to Iran and found himself detained by intelligence officials. He's one of several opposition figures in exile who have been returned to Iran over the past year.
France previously has criticised his death sentence as "a serious blow to freedom of expression and press freedom in Iran".
A series of a televised confessions aired earlier this year over his work.
During an interview on July, Zam said he has lost some 30kg since his arrest in October 2019. He said following the arrest that he could meet his father after nine years and his mother and sister after some six years.
Zam is the son of Shiite cleric Mohammad Ali Zam, a reformist who once served in a government policy position in the early 1980s. The cleric wrote a letter published by Iranian media in July 2017 in which he said he wouldn't support his son over AmadNews' reporting and messages on its Telegram channel.
Associated Press writer Jon Gambrell in Dubai, United Arab Emirates, contributed to this report.