Their closed Facebook group "League of LOL" — made up mostly of privileged white men in their thirties — ridiculed and harrassed women journalists for years, sometimes using pornographic memes to attack them. Women seen as feminist were the group's favourite targets.
The founder of the group, journalist Vincent Glad, was suspended Monday by left-wing daily Liberation after an investigation by the newspaper's own fact-checking unit exposed its existence.
The revelations also led to the suspension of the newspaper's online editor Alexandre Hervaud and his opposite number at France's trendiest music and culture magazine, Les Inrockuptibles, David Doucet.
Victims of the group recounted how the attacks and pranks had pushed one woman to quit journalism and left another suicidal.
League of LOL targeted science presenter Florence Porcel, seeking to humiliate her by getting group members to pose as the producers of a prestigious television programme offering her a job, then posted the recording of the fake interview online.
Other women had their heads grafted onto pornographic images.
Set up in 2009, the League of LOL also had members in public relations, graphic design, and media eduction. It had been less active in recent years.
The head of a porn culture website stepped down Monday and suspended his Le Tag Parfait (The Perfect Tag) blog, apologizing for his part in the activities of the group that gets its name from the acronym for "laugh out loud."
Stephen des Aulnois admitted the League of LOL was guilty of "repeated online harassment. I apologize to all those I hurt and harassed... I am also guilty of silence and inaction during all those years when I knew."
Group-founder Glad, who is on a freelance contract at Liberation, at first denied it was a sexist crusade.
"There was never an anti-feminist obsession inside the group. We make fun of everything and everybody," he insisted.
But in a lengthy apology on Twitter, Glad said he was "horrified to now see my tweets from 2013 when I joked about rape culture. I am ashamed."
Glad said he "had not realized until today how sexist our stance was. I didn't see how our jokes were shutting down the first wave of feminists speaking out on social media.
"I had the stupid reaction of many men at the time — why are they annoying us with all this?" he added.
Christophe Carron, editor of the French edition of online magazine Slate, also admitted having been a member of the group.
Journalist Melanie Wanga, who said she quit Twitter for several years because of abuse, tweeted that the harassers were finally getting their comeuppance.
"Imagine being a young, black woman journalist talking about blackface and apartheid and getting this stuff (racial and sexist harassment) multiplied by 20 from your 'colleagues'," she said. "You can see these harassers erasing all their dodgy tweets and talking about equality and regurgitating the work of all the feminists they attacked to buy themselves a new virginity," she added
France's minister for digital affairs, Mounir Mahjoubi, described the men behind League of LOL as "losers," but social media tweeters highlighted the men where actually powerful and influential.
The newspaper Liberation also revealed the existence of another male misogynistic group called Radio Biere Foot ("Radio Beer Football") at the French branch of the Huffington Post, resulting in the lay-off of three journalists.
The online magazine L'Express revealed another similar group within the media Vice, also targetting women journalists.
Online harassment can be prosecuted from the past six years: under the French law, only law-breaking posts after 2013 could be prosecuted.