The 320-page book Merci pour ce moment (Thank You for this Moment) in a bookstore in Paris. Photo: Charles Platiau/Reuters

French President François Hollande has felt the sting of a woman scorned as his former partner Valerie Trierweiler reveals all about his alleged infidelities in a new book.

Trierweiler, France’s first lady until earlier this year, paints a harsh portrait of her ex-lover, describing him as a “mean liar” who perpetuates a “cycle of infidelity”.

And her claims that he despises the poor will do nothing to help the image of the Socialist leader.

The couple split in January amid reports Hollande was having an affair with French actress Julie Gayet, which he did not deny. “Private affairs should be handled privately,” he said at the time.

In her 320-page Thank You for this Moment published on Thurdsay, Trierweiler describes her relationship with Mr Hollande in sharp and biting detail, from their first kiss to their break-up after the Gayet affair emerged.

It is the most elaborate and public account yet of the president’s alleged infidelities.

Hollande’s office has declined to comment.

According to Trierweiler, the relationship was born of infidelity and died from it.

She claims that they almost tied the knot: She wrote that he proposed in September 2012 and they planned a private wedding just before Christmas. But with about a month to go, Hollande abruptly called off those plans, she wrote.

“Julie Gayet was already in his life, but I didn’t know,” wrote Miss Trierweiler, a long-time journalist with Paris Match magazine.

When Trierweiler fell in love with Hollande, the mother of three was married, and he was the long-time partner of Segolene Royal, also a Socialist politician, and father of their four children.

They split in 2007, two years after his affair with Trierweiler began.

Trierweiler lamented that she has been seen by many as the destroyer of the “mythic couple” of French politics: Royal was the Socialist nominee in the 2007 presidential race, but lost.

“I appear to everybody as the temptress, the mean one, the home breaker,” Miss Trierweiler wrote.

She said she discovered his tryst with Gayet just days before gossip magazine Closer published photos of him in a motorcycle helmet reportedly going to a secret rendezvous with the actress.

Trierweiler confronted him about it and she was later admitted to hospital for about a week. Somewhat unexpectedly for a politician who years ago quipped about his dislike of rich people, Trierweiler wrote that Hollande “doesn’t like the poor” and once disdainfully referred to them as “toothless”.

But support for Hollande came from Royal –the ecology and energy minister now in his Socialist Cabinet.

She defended him telling BFM-TV that he was an ardent defender of the poor while he was a regional governor years ago.

As several Paris booksellers reported brisk sales, some shoppers bemoaned the book’s unflattering revelations.

“Surely it gives a deplorable image of our president,” Jean-Pierre Geoffroy said at a Paris bookstore. “It’s vengeance and it’s not very honourable of her.”