A book about a night of opium-fuelled cross-cultural dreaming won 's most prestigious -- and lucrative -- literary prize Tuesday in a contest dominated by the West's fraught relationship with Islam.

took the Goncourt prize with "Boussole" ("Compass"), a poetic eulogy to the long history of cultural exchanges between East and West that flies in the face of cliches about the so-called clash of civilisations.

The novel runs the course of a night of opium-induced ruminations, and in the spirit of his high-flown odyssey, its burly author told a scrum of reporters that 's patron saint and the ghost of 's most revered Islamic thinker may have had a hand in his victory.

"I have just come back from and ," said Enard, 43, a scholar of both Arabic and Persian. "Maybe it was the luck that Sheikh Abderrahmane (a historian who died in 2010) and Saint George of brought me...

"I am extraordinarily happy," he added, after fighting his way into the restaurant where the prize was decided over lunch by the Goncourt's jury, who are all elected for life.

The novel has already won the booksellers' prize -- the Nancy-Le Point -- for its nimbly erudite voyage from the Islamic enlightenment of the Middle Ages to present day executioners in war-torn .

Enard has also been compared to the 19th-century great Balzac -- though less for his prose as passion for food and his physique, honed at some of the best tables in Paris and the Middle East.

Although Enard had been the clear critics' favourite, the daring and density of his writing -- the opening sentence lasts a page -- put others off.

The head of the jury, said after the award: "You have to be audacious to write a book like this, and you also have to be audacious to read it."

But the Barcelona-based Enard insisted his book was "very accessible... I write very simply. All you have to do is open the book to realise that it not as hard to read as some say."

An academic who has lived in , and , where his breakthrough novel "Zone" (2008) is set, Enard also won 's second most lucrative prize, the youth Goncourt, in 2010.

- Prize decided over lunch -

"I like a winning book which tells of the world in which we live," the head of the jury, , told French radio on the eve of the often-heated final judging lunch, this year fought out over lamb stew with olives and sundried tomatoes.

Although the victor gets only 10 euros ($11) in prize money, the Goncourt almost guarantees a boost in sales of 450,000 copies or more, placing it instantly among the year's bestsellers.

All four novels in the final reckoning for the oldest literary prize in the French-speaking world dealt in one way or another with the Middle East or the long twilight of 's colonial entanglement in the region.

The Algerian writer was long the odds-on favourite for the prize but failed to make the final cut last week with his dystopian vision of a future Islamic caliphate, "2084", its title a nod to 's classic "1984".

Sansal had the strong backing of , 's most famous literary provocateur, who also has Islamists in his sights in his latest offering "Submission".

With Sansal out, many had thought the smart money was on "Les Preponderants" (roughly translated as "The Principals"), by veteran Franco-Tunisian author .

- 'Cruel and stupid tyranny' -

The fact that the Goncourt jury chose to reveal its final four novels in , where Kaddour, 70, was born, seemed also to indicate they were leaning his way.

Pivot said the announcement in the city's Bardo Museum, where jihadist gunmen killed 22 people last March, was show support the country's fledgling democracy in the very place "where the most cruel and stupid tyranny had shown its contempt for freedom".

There was also disappointment for and his "Ce pays qui te ressemble" ("This country that you resemble"), with its tales of the Jewish of his childhood.

The fourth nominee and only woman on the shortlist was , whose love story "Titus n'aimait pas Berenice" ("Titus does not love Berenice") also had a Middle Eastern twist.

Delphine de Vigan won the parallel Renaudot prize for her already bestselling Stephen King-inspired thriller "D'après une histoire vraie" ("From a true story").

Only six women writers have ever won the Goncourt in its 112-year history, including Lydie Salvayre last year for "Pas pleurer" ("Don't cry"). afp