- A new book says France's first lady began seeing Hollande while dating another man
- Valérie Trierweiler is known for her strong character
- The book says Sarkozy also made a pass at Trierweiler, who is not married to Hollande
France's first lady is filing a defamation complaint against the authors of a biography published Thursday which claims she had an affair with a former French minister while seeing President Francois Hollande.
Attorneys for Valérie Trierweiler, who is not married to Hollande, told CNN the complaint is likely to be filed Friday with the Paris tribunal.
In "La Frondeuse," or "The Troublemaker," authors Alix Bouilhaguet and Christophe Jakubyszyn allege that Trierweiler had a longstanding relationship with Patrick Devedjian, a former minister for economic recovery and close ally of former President Nicolas Sarkozy.
This relationship allegedly started in 1998 and ended only in 2004 -- four years after her courtship with Hollande began. All of them had other partners at the time.
Trierweiler's relationship with Devedjian crumbled after he was unable to commit further to their relationship, the book says -- paving the way for Hollande to step in.
Several books have been published about Hollande and his romantic partners since he was elected.
"Trierweiler is an interesting subject matter because she has character," Bouilhaguet told CNN. "It's complicated for a 47-year-old woman to find herself in the Elysée, which has demanding protocol for their first ladies."
Bouilhaguet admitted that she was "surprised" by the defamation complaint, adding that the book is an "open investigation with a true look" at Trierweiler's personality.
In another extract in the book, the authors write that Trierweiler claims Sarkozy made a pass at her at a July 14 celebration in the Elysée Palace, while holding his ex-wife Cecilia's hand. "You're so beautiful," he is said to have whispered in her ear.
When she refused his advances, the book says, Sarkozy said to his friends: "Who does she take herself for? Am I not good enough for her?"
Trierweiler is characterized by this "abrupt iciness," the authors claim, and inside journalist circles at French newspaper Le Monde, she was labeled "Cruella." A friend of the couple goes even further and says in the book that Trierweiler is the "Achilles heel" of Hollande, who can "potentially create a lot of problems for him."
The authors also called the French first lady a "narcissistic woman, using at once her charms to get what she wants and in the following second, showing her fangs when something displeases her."
Hollande's complex love life -- including alleged animosity between Trierweiler and Segolene Royal, with whom he has four children -- was the subject of two books published this summer. A poll in August suggested that it was at the root of his sliding popularity.
Trierweiler was embroiled in controversy in June after she tweeted support for Royal's opponent during the French parliamentary elections.