The mostly female demonstrators in Paris waved placards bearing the #Metoo hashtag and its French equivalent #Balancetonporc (Grass up your pig), which have used by tens of thousands of women in the past two weeks to share accounts of being sexually harassed or abused.
Similar gatherings were held in Marseille, Bordeaux and Lille, among other cities.
The aim was to ensure the campaign reached "beyond the social media buzz", according to organiser Carol Galand, a freelance journalist.
French celebrities accused
Ramadan reacted to two rape accusations for the first time on Saturday evening, claiming it was a "campaign of calumny" on his Facebook page.
Feminist groups were due to demonstrate on Monday evening outside the Roman Polanski retrospective at the Cinémathèque Française film archive.
Wanted in the US for the statutory rape of a 13-year-old girl in the 1970s, Polanski now face an investigation into rape allegations in Switzerland, meaning that he faces at least four accusations of sexual assault.
"The Cinémathèque could have thought of a woman artist considering how few of them have been honoured by them in the last few years," Marie Allibert of organisers Osez le Féminisme! told RFI. "The fact that they are still persisting with this Polanski retrospective, despite the worldly context of women speaking about sexual assault and women finally trying to denounce what they've been victims of, is particularly shocking."
Allibert rejected the idea that an artist's work should be judged independently of his personal behaviour.
" If I make a comparison, no one would ever suggest such a thing regarding, I would say, an ordinary man, for example an employee, a doctor, a banker, she said. "It would sound really silly and shocking to say 'Oh I know this man killed his wife, but he's such a good doctor, I'm still going to go and see him'.
Artists and celebrities should not be above the law, she argued.
"And Polanski is here in person, so he is being honoured and praised, no matter what the ministry of culture says. It cannot only be his work, it's him himself who's here tonight."
In October, before the Weinstein scandal erupted, the French government launched a consultation ahead of drafting a law against sexism and sexual violence.