Julie Gayet, the actress linked to President François Hollande, is suing French magazine Closer after it reported they were having an affair.
The actress is seeking 50,000 euros (£41,000) in damages and 4,000 euros in legal costs for breach of privacy, Closer magazine told news agency AFP today.
If she wins, the magazine will have to publish the legal verdict on its cover page.
The seven-page spread featured a series of photographs of a man, identified as President Hollande, wearing a black motorcycle helmet entering her apartment in Paris and leaving the next morning accompanied by security. The magazine said the President could be recognised by his shoes.
Earlier this week, Closer said it was on track to sell 600,000 copies of the affair Hollande edition- twice its usual circulation. The magazine said it will unveil new details and photographs in its next edition, which is set to hit the stands on Friday.
In a news conference on Tuesday, Hollande told reporters he would not sue the magazine for publishing the images, but insisted that his "indignation was total".
The French president admitted he was going through a difficult time but refused to discuss the alleged affair saying private matters should be dealt with privately. He failed to clarify long-term partner Valerie Trierweiler's status as France's First Lady.
She remains in hospital where she has been "resting" following the exposure of his alleged affair with the 41-year old actress. The French president has not visited Trierweiler since she checked into a Paris clinic six days ago.