Cyril Hanouna used a feminine tone of voice and tricked those he spoke to into revealing their sexual fantasies.
One of the victims was left in a "state of appalling distress", LGBT campaigners said.
They accused the presenter of homophobia.
Nearly 20,000 complaints about the segment on Mr Hanouna's nightly show Touche pas Ã  mon poste (TPMP - "Don't touch my TV" in English) had been made to the media regulator by Monday afternoon, reports said.
Mr Hanouna had posed online as a bisexual man called Jean-JosÃ© who was "very sporty and well endowed" and "liked being insulted", Ouest France newspaper reported.
He engaged in suggestive chat with the men who responded as guests, a studio audience and more than a million viewers watched.
Nicolas Noguier of Le Refuge, an association that works with young victims of homophobia, wrote on Facebook that one hotline operator had spent most of the night talking to one of the men Mr Hanouna deceived.
"We were devastated by his tears and his fear of being found out by his parents and those around him," Mr Noguier said.
JoÃ«l Deumier, president of SOS Homophobie said the segment was "scandalous, shameful and homophobic".
"When you let people get away with behaviour like this, you trivialise homophobic discourse. The sketch was deeply homophobic," he said, quoted by the Gay Times.
Mr Hanouna said on Friday that he felt "hurt" by allegations of homophobia and said it was "everything he had been fighting against for years and the opposite of TPMP".
The presenter had also used a photo of YouTube star Max Emerson's torso for the profile picture without permission, the Gay Times reported. Mr Emerson has spoken out on social media, saying he hopes Mr Hanouna "learns a lesson".
Mr Hanouna's show has been the subject of complaints about sexism and homophobia before.
In October a male guest on his show kissed a female guest on her breast after she rebuffed his requests for a kiss.
That prompted more than 250 people, including then women's rights minister Laurence Rossignol, to complain to the regulator.
A record number of people have complained after a French TV presenter posted a spoof ad on a gay dating website and made fun of people who responded live on air.