President François Hollande is considering legal action after the French version of Closer magazine has published seven pages alleging that he was having an affair with a 41 years old actress.
The Elysée Palace said that the president might sue for breach of France's strict privacy law but did not specifically deny the allegations.
Under the headline "The secret love of the President," Closer published images of an unrecognisable man in black motorcycle helmet arriving at the Paris flat of the actress Julie Gayet on New Year's Day. The magazine said that the president was recognisable from "his shoes".
It said that a second man in the images, also wearing a motorcycle helmet, was identifiable as an Elysee security officer. The second man is seen returning to the flat with what the magazine says is a bag of croissants.
The Elysée said this morning: "Francois Hollande greatly deplores the invasion of his privacy, to which he has a right as any other citizen does. He is studying what action, including legal action, to take following this publication."
The French version of Closer drew worldwide condemnation in 2012 for publishing topless pictures of Kate Middleton.
Unconfirmed rumours of an affair between Mr Hollande, 59, and Ms Gayet have been circulating in Paris for months. The actress is currently appearing as a vampish diplomat in a comic film about the French foreign ministry, "Quai d'Orsay.
Mr Hollande, who has been president for 20 months, is in an unmarried relationship with the former journalist, Valérie Trierweiler, 49. Ms Trierwwiler performs the duties of "Première Dame or First Lady.
The President has four grown-up children from a previous common law marriage with Ségolène Royal, who was Socialist presidential candidate in 2007.
Closer magazine speaks of "astonishing photographs… which also pose questions about the security of the President.
"The Head of State is accompanied by a solitary bodyguard who protects the secrecy surrounding these encounters with an actress and even brings them croissants."