What is it with the French? What has given them the right to claim the inside track on ooh-la-la, the routine activity that propagates the species? One of the strengths of Judith Thurman’s massive biography is its grasp of the evolution of French social and sexual sensibility, from the Revolution to the Occupation.

Whatever the causes of French erotic self-admiration, the novelist Colette (born 1873, died 1954) set out to embody and propagandise it. This pretty woman with the triangular face and pert, knowing eyes churned out, from the age of twenty-four, naughty but well-written books which preached that she, and her nation, understood the secrets of the flesh better than the rest of the world, and practised them better, too. She cultivated a promiscuous bisexual lifestyle to underscore her message. Even as a girl, she posed with aggressive suggestiveness on the garden swing, her long plaits suggesting Miss Whiplash as well the gymslip virgin.

Born in the Burgundian village of Saint-Sauveur, as Sidonie-Gabrielle Colette, to an adulterous, loving but fiercely chastising mother and a one-legged former army officer, she married at twenty. She was besotted with her choice, Henry Gauthier-Villars, a ‘pudgy erotomane’ in Thurman’s good phrase. Otherwise known as ‘Willy’, he was an experienced rake, writer and music critic who, fourteen years senior to his bride, liked to pretend that he was even older. (See Gigi coming up?) Willy poured out articles and books, partly by getting others to write some for him. In 1900, he published under his own name his wife’s manuscript, Claudine at School, the supposed journal of a rebellious, sexually adventurous sixteen-year-old schoolgirl. Many ‘Claudines’ followed, in an apprenticeship that was part exploitation, part tutoring of Colette’s gift. By 1902, when the sequel, Claudine in Paris, had been turned into a play and Willy had marketed product spin-offs, from face powder to cigarettes, every whorehouse in Paris had a resident ‘Claudine’.

Colette by then was recognised as an author in her own right, but also as a hard-working touring music- hall actress. Both she and Willy had many lovers, in a bedroom farce of an open marriage, which was enacted on the Parisian stage as En camarades – a comic play Colette wrote in 1909 as her own star vehicle, with her transvestite lesbian lover as her co-star and leading man. The marriage ended in a not-so-comic divorce in 1910 after much legal wrangling over royalties and copyright. Her work, now under her own name, was more and more admired for its spare, lean prose and its unromantic view of the sexual connection. She wrote as an independent modern woman who took her pleasure like a man.

Husband Number Two, acquired when she was thirty-nine, was more respectable: Baron Henry de Jouvenel, an influential political journalist of good family. The marriage was preceded by pregnancy – the first for Colette, who by now was a celebrated writer, music-hall star, and journalist. She put in the regulation nine months, but her main emotion upon producing a daughter was relief at finding that her body had lost none of its erotic vigour. She handed over the baby, coldly and absolutely, to the care of a nanny, and carried on shagging.

In her late forties (the unwanted daughter packed off to boarding schools), Colette acquired a trophy lover in the form of her sixteen-year-old stepson, a gaunt, handsome, co-operative lad. Thus did she play Phèdre: Racine’s model of the French ideal of the older-woman-younger-man combination. The affair went on for nearly five years. As Thurman makes clear, Colette was funny about food as she grew older. Greedy herself, she grew corpulent but no less lustful and maternally insisted on weighing her young lover every day. Spotting the two together was a Paris sport. Colette and the boy’s father divorced in 1925. It was time for Husband Number Three.

While Colette was, according to Thurman, casually anti-Semitic like many of her countrymen, prejudice did not prevent her from making a loving marriage with Maurice Goudeket, a stylish, courtly Jew, -a pearl- seller, thirty-five to her fifty-one, who outlived her. There were a few bad months when Goudeket was picked up by the Gestapo in 1941 and interned at Compiègne until her German connections in Paris got him released. With her man all right, although in hiding, Colette had little sympathy left for the other French Jews who were rounded up. Was she a German sympathiser? Maybe. Mainly she saw herself as a writer, one so interested in her work that she could indulge in moral lethargy. What she did during the Occupation was to write, among other things, Gigi. Venerated, awarded the Prix Goncourt, Colette spent her seventh decade as an ancient sacred monster with kohled eyes and frizzy hair, lying on a mattress in a small flat tucked into the Palais-Royal, blessing the devoted husband who tended to her needs before going out to his numerous lovers … Yawn.

Husbands, lovers, mistresses, bare breasts, opium dens, lesbian covens, all whirl by in an indistinguishable blur in this over-long book, punctuated by over-long summaries of the plots of innumerable novels and plays. This is that rare biography in which the background is better handled than the life in question. Thurman, award-winning biographer of Isak Dinesen, here drowns in detail. Her account of the Dreyfus Affair is brilliant, perhaps because Colette hardly gets a mention. (For good reason: Colette was as uninterested in politics at the end of the century as she was during the Second World War.) But she fails to persuade that Colette, specialist in the flesh, understood the human heart or conscience.

In her life as in her art, Colette seems to have confused pleasure and pain, and not known when real tears were called for. Her best-known work, the story of the little girl groomed to be the courtesan of a rich gentleman, was long considered a comic masterpiece. Today Gigi reads like a paedophile’s dream- something that belongs on the Internet.