A satirical fake news website named The Resistance: Last Line of Defence posted an article titled "BREAKING: DOJ Officially Labels Antifa A Terrorist Group" which opened:
It's been a long time coming, but the fascists calling themselves an anti-fascist movement are finally labeled what they are by the Department of Justice: a hate group.
Recently, the Antifa terrorists have been storming free speech rallies to fight against...free speech. To date, 163 innocent people have been attacked, beaten, and subjected to horrible treatment from the "tolerant Left."
"From this point on, each and every member of Antifa who attacks an innocent person will be charged with terroristic acts," Attorney General Jeff Sessions announced Tuesday. "This has gone on long enough."
The Jeff Sessions quote is fake, there is no mention of it anywhere else on the internet except in copies of this article. And the photo used with the article has also been debunked as fake: it shows a violent protest in Greece (check the European style traffic signs in the upper right corner) with the Antifa logo digitally added later.
On top of that, The Resistance: The Last Line of Defense carries following disclaimer:
In a cynical world where the news of the day often seems fake, The Last Line of Defense offers today's busy conservative a place to go to read things they'll enjoy and congregate with a bunch of people they agree with. So while everything on this site is a satirical work of fiction, we are proud to present it to those who will have called it real anyway.
That didn't stop at least several fake news sites (archived, archived, archived) from copying and spreading the story. If you see anyone spreading it around, don't hesitate to send them over here for a dose of real information. And note that even though there is a real petition on change.org to declare Antifa a terrorist organisation DOJ policy is generally not set via internet petitions.