Argento delivered a speech on 20 May 2018, following the 2018 Cannes Film Festival, calling the festival Weinstein's "hunting ground", alleging that she was raped by Weinstein in Cannes when she was 21. She added, "And even tonight, sitting among you, there are those who still have to be held accountable for their conduct against women."
On August 19, 2018, The New York Times published allegations that Argento sexually assaulted actor Jimmy Bennett. Argento had first met Bennett when he played her son in the 2004 film The Heart Is Deceitful Above All Things when Bennett was 7 years old. The alleged assault occurred in 2013 when he was two months past his 17th birthday in a hotel room in California where the age of consent is 18; Argento was 37 at the time. According to Bennett, in their encounter Argento gave him alcohol, performed oral sex on him and had sexual intercourse with him. Argento had quietly arranged a $380,000 nondisclosure settlement with Bennett in the months following her revelations regarding Weinstein. Bennett said when Argento came out against Weinstein, it stirred memories of his own experience in 2013. He imparted he had sought to resolve the matter privately, and had not spoken out sooner "because I was ashamed and afraid to be part of the public narrative." In a statement provided to the Times, he said: "I was underage when the event took place, and I tried to seek justice in a way that made sense to me at the time because I was not ready to deal with the ramifications of my story becoming public. At the time I believed there was still a stigma to being in the situation as a male in our society. I didn’t think that people would understand the event that took place from the eyes of a teenage boy." Bennett said he would like to "move past this event in my life," adding, "today I choose to move forward, no longer in silence."
Argento denied the allegations, claiming that she never had a sexual encounter with Bennett and that when he made a request for money to her, her partner Anthony Bourdain paid him to avoid negative publicity. On August 22, she released a statement reading: "I strongly deny and oppose the contents of the New York Times article dated 20 August 2018, as circulated also in national and international news. I am deeply shocked and hurt by having read news that is absolutely false. I have never had any sexual relationship with Bennett." A spokeswoman for the Times responded, "We are confident in the accuracy of our reporting, which was based on verified documents and multiple sources." Fellow #MeToo advocate Rose McGowan initially expressed support for Argento and implored others to show restraint, stating, "None of us know the truth of the situation and I'm sure more will be revealed. Be gentle." McGowan faced criticism on social media for her comments, which contradicted the #MeToo movement's message of believing survivors. Following Argento's denials, a photograph of her topless in bed with Bennett was published, as well as her alleged admission of sex with him in text messages to model Rain Dove. In the screenshots, Argento reputedly stated: "I had sex with him it felt weird. I didn't know he was a minor until the shakedown letter." In a letter published online in September 2018, Argento's attorney admitted there was a sexual encounter, but claimed Bennett "sexually attacked" Argento. Amid the allegations, it was announced that Argento had been dropped as a judge on X-Factor Italy.