“You have big breasts. You are my type of woman. I will make you orgasm all night,” she quoted him as having said, at what she later described as a social event during a television festival in Cannes, on the French Riviera.
Ms. Muller said in a statement published on Facebook on Wednesday that Mr. Brion was now suing her for defamation and was asking for 50,000 euros in damages (about $61,200), as well as €10,000 in legal fees (about $12,200) and the publication at her expense of the court’s ruling in media outlets.
“I will go to the end of this fight with the help of my lawyer and I hope that this trial will be an opportunity to have a real debate on ways of fighting against sexual harassment,” wrote Ms. Muller, who in December was included by Time magazine as one of the “silence breakers” it named person of the year for 2017.
A lawyer for Mr. Brion confirmed the suit, but declined to comment further. In an interview published in the newsweekly Le Point on Thursday, Mr. Brion said his life had been upended by the accusations.
He said that some media outlets incorrectly referred to him as a former boss of Ms. Muller, that he was targeted by demeaning social media posts, and that he lost multiple job opportunities.
“I am surrounded by good people, I was lucky enough to go abroad to take a step back, but are we thinking about the effect that this kind of outpouring can have on a fragile personality?” Mr. Brion said.
In his interview with Le Point, and in an op-ed published in December in Le Monde, Mr. Brion acknowledged he had made the crude comments.
“Nevertheless, what does my conduct have to do with the case of Harvey Weinstein, who is accused of rape and sexual assault by several women?” Mr. Brion wrote in Le Monde, stressing that the comments were made only once, under the influence of alcohol, that he did not work with Ms. Muller, and that he had apologized soon after.
But Alexis Guedj, Ms. Muller’s lawyer, said in a phone interview that his client worked in a field where a wide range of settings could be considered akin to a workplace, even though Mr. Brion was neither a colleague nor a superior of Ms. Muller.
“There has to be a debate on this issue: Is a professional relationship the same in all professions?” said Mr. Guedj, who argued that social events like cocktail parties could be considered in some fields, like the media, as professional settings because deals are struck and hiring decisions are made. He noted Ms. Muller’s publication had written about Equidia and Mr. Brion on several occasions.
The case is not expected to go to court for several months.