French police have arrested a woman in connection with the release of a sex video that brought down a political ally of President Emmanuel Macron.
Alexandra de Taddeo is the girlfriend of activist Petr Pavlensky. Both were detained on Saturday but police did not initially reveal her arrest.
She was arrested on charges of invasion of privacy and distributing personal images without consent, officials said.
The video scuppered Benjamin Griveaux's candidacy for mayor of Paris.
It was published on a little-known website that alleged Mr Griveaux, 42, had exchanged intimate mobile phone messages and footage with a young woman.
Ms de Taddeo is suspected of being the recipient of the intimate footage, France's Le Figaro newspaper reported on Sunday, quoting the Paris prosecutor's office.
Mr Pavlensky, a Russian who sought asylum in France in 2017, earlier said that he was responsible for posting the video, which showed a man involved in a sexual act.
He was detained on Saturday as part of a separate investigation into an alleged brawl in Paris on 31 December involving "wilful violence with a weapon".
Prosecutors later said that Ms de Taddeo, whom he had reportedly been in a relationship with since January 2019, was being held over the widely condemned release of the footage of Mr Griveaux.
The politician had filed an invasion of privacy complaint hours before she was detained.
What was the video's impact?
The distribution of the clip, which spread quickly across social media last Thursday, brought condemnation from across the political spectrum.
Paris Mayor Anne Hidalgo said people's private lives should be respected.
Far-left leader Jean-Luc Mélenchon condemned the video's release as "odious", while far-right leader Marine Le Pen suggested Mr Griveaux should not have quit.
Mr Pavlensky has said he posted the video to expose what he sees as the politician's hypocrisy.
Mr Griveaux, who is married with children and was once a government spokesman, condemned the distribution of the video as he withdrew his mayoral candidacy on Friday.
"My family does not deserve this. No-one should ever be subjected to such abuse," he said.
On Sunday, French Health Minister Agnès Buzyn said she would be replacing Mr Griveaux as the En Marche party's candidate for mayor of Paris.
Who is Petr Pavlensky?
The 35-year-old first gained notoriety by nailing his scrotum to Moscow's Red Square in 2013. He fled Russia and sought asylum in France when he was accused by the authorities of a sexual assault that he denied.
He served seven months in jail for setting the front door of the FSB intelligence agency on fire in Moscow and later caused minor damage to a Banque de France branch by setting that alight.
Before his arrest, he told French news channel LCI that Mr Griveaux was only the first politician that he would target, saying he would carry on fighting the "propaganda and puritanism of politicians".
French media have traditionally avoided prying into the private lives of people in public life and a number of figures have referred distastefully to the "Americanisation" of politics.