PARIS (AFP) - French-Senegalese writer Marie NDiaye on Monday won France's top literary prize for a haunting novel on family, betrayal and the hellish ordeal of illegal migration from Africa.

NDiaye, 42, becomes the first woman in a decade to win the Goncourt prize for her latest work, "Trois Femmes Puissantes" (Three Powerful Women), which shot to the top of the book charts upon its release earlier this year.

Like much of her work, the book touches on the troubled ties between Africa and its former colonial rulers, and between blacks and whites.

Set between France and Senegal, the three-part novel weaves together the stories of women whose lives straddle the two continents and who are weighed down by family secrets, humiliation and betrayal.

"I am very happy to be a woman receiving the Goncourt," the elegant young woman, hair pulled back in a chignon, told reporters at the award ceremony in a Paris restaurant. "The book's success was already a miracle of sorts."

"This prize is an unexpected reward for 25 years of persistence."

Ndiaye published her first novel aged 17, and has since carved out a place in the French pantheon as a novelist, screenwriter and the only living playwright in the repertoire of the Comedie Francaise.

"Her voice, perfectly clear and original, rises above the chatter," wrote Le Monde of her latest book.

She is also the first black woman laureate of the Goncourt in history, but the soft-spoken writer denies she is a "symbol."

"I have never thought of it in those terms: 'black woman' and 'Goncourt'. I find it impossible to see things that way," she told AFP in a recent interview.

Raised by her teacher mother in the provincial town of Pithiviers south of Paris, after her father returned to Senegal, NDiaye has French nationality and did not travel to Africa until she was in her twenties.

"I grew up in a world that was 100-percent French. My African roots don't mean much, except that people know of them because of the colour of my skin and my name," she said recently.

NDiaye recently co-wrote the film "White Material" starring Isabelle Huppert, with French director Claire Denis, set in west Africa and about whites terrorised by roving child soldiers.

She insists she has "met many French people raised in Africa who are more African than I am."

Part one of "Trois Femmes Puissantes," which blends stream of consciousness with forays into the supernatural, follows a young woman lawyer from Paris to Dakar on a difficult pilgrimage to the home of her estranged father.

The second story is told through the eyes of an African woman's French partner, who has dragged her back to a mediocre existence in France and where both their lives are clouded by demons from his past.

The third follows the plight of a destitute young woman who is forced to join the migrant route from Senegal towards the European El Dorado, a brutal illustration of what NDiaye calls "a modern-day tragedy".

"The story of these migrants has been told many times before, but if this can help people understand their fate a bit better, I will be happy," she said as she received the Goncourt.

The prize itself is only worth 10 euros (15 dollars), but promises celebrity status and a boost in book sales.

NDiaye moved to Berlin with her writer husband and three children just after the 2007 presidential election, and says she finds victor President Nicolas Sarkozy's France "monstrous" and "vulgar".

She also wrote the preface to a recent book by her brother Pap NDiaye, a prominent historian and campaigner for minority rights.

Yet NDiaye denies she is pushing a political message in her work.