French President Francois Hollande says he is considering suing a magazine after it claimed he was having an affair with an actress.
Mr Hollande described the report as an “attack on the right to privacy”, but did not deny the allegation.
The latest edition of the weekly tabloid Closer features seven pages of revelations and photos about his alleged affair with Julie Gayet.
Ms Gayet, 41, is an established television and cinema actress.
She has appeared in more than 50 films, and once appeared in one of Mr Hollande’s election campaign television adverts.
Rumours of their alleged relationship have been circulating on the internet for many months.
Last March, she filed a complaint with prosecutors in Paris against various bloggers and websites that were reporting on the rumours.
Her lawyer at the time said there was no basis to the claims. She has not yet commented on the latest developments.
Mr Hollande’s official partner is Valerie Trierweiler, a journalist for whom he left fellow Socialist politician Segolene Royal, the mother of his four children.
Mr Hollande told the Agence France Presse news agency that he “like every other citizen has a right” to privacy.
In a statement issued personally rather than by his office, he said he was “looking into possible action, including legal action” against Closer.
But he does not deny the allegation of an affair, the BBC’s Hugh Schofield in Paris points out.
The magazine’s print edition came out on Friday and shows pictures it claims support rumours that the 59-year-old president routinely spends the night with Ms Gayet at a flat not far from the Elysee Palace.
The pictures purportedly show the pair arriving separately. Mr Hollande, wearing a helmet, is on a motorbike driven by a chauffeur.
The magazine claims the president’s bodyguard arrives the following morning to deliver croissants.
Closer defended its publication of the photos, saying the “surprising images” raise a question about the security of the president.
But the magazine’s editor Laurence Pieau said the images should not be “over-dramatised” and described Mr Hollande as a “normal president” – a phrase he himself has used to define his style of leadership.
“He’s a president who has a crush,” she told Europe 1 Radio.
Closer magazine has run up against France’s strict privacy laws – which make it a criminal offence to publish information about a person’s private life without their express permission – in the past.
The British royal family took legal action against the magazine in September 2012 after it published photos of the Duchess of Cambridge sunbathing topless on a private holiday in France.
Ms Pieau – along with two photographers and the magazine’s publishing director Ernesto Mauri – has since been charged with breaching privacy laws.
French political commentator Anne Elisabeth Moutet told the BBC the magazine was unlikely to have gone with the story about Mr Hollande’s alleged affair “without being quite sure that they had something on it”.
“And what’s very interesting is that this was immediately picked up by one of the very respectable news magazines, Le Point,” she said.
It was unlikely legal action could now suppress the story, Ms Moutet added.
President Hollande, who took office in May 2012, has seen public support slipping recently. One poll in November gave him just 15% support, the lowest for any president in the last 50 years.
But he had some support on the streets of Paris following Closer’s revelations.
“I find it low, frankly it’s not interesting. He [the president] can react the way he wants, it’s his private life no matter what,” one man, Jean-Christophe, said.
French people have historically been tolerant of their leaders’ infidelities – with revelations making little impact on poll ratings.
Former President Jacques Chirac was a known ladies’ man, once confessing: “There have been women I have loved a lot, as discreetly as possible.”
His predecessor Francois Mitterand kept secret a mistress and daughter for much of his presidency, only acknowledging them shortly before his death in 1996.