Carla's collection: Baroque and roll lifestyle

A decade has passed since Carla Bruni, one of the first crop of supermodels, was seen on every catwalk, wearing Prada, Chanel, Christian Dior and Givenchy. She had come to attention 10 years before that, aged 19, when picked to be the image of Guess, and for years she was as recognisable as Naomi, Kate and the rest.

Then she called it a day and vanished. When she came back, it was as a singer-songwriter.

A poster girl, a catwalk icon, a pop star - a queen, it would seem, of reinvention, destined to live each phase of her life in the public eye.

Now we learn an extraordinary sale at Sotheby's next month will even tell us of her baroque pre-history, as the Bruni family's extravagant heirlooms are set to go under the hammer.

She is something of a phenomenon, this woman. Now 39, in her last full year as a model in 1998, she made $7.5m according to Business Age magazine. She is the femme fatale who began an affair with Mick Jagger in 1991 when she was 22 and kept it going intermittently for the next seven years, to the very public (and ultimately terminal) exasperation of Jerry Hall.

When she was not provoking Mick, once again, to abandon Richmond for Paris, she was dating a weird assortment of zillionaires and celebs, including Donald Trump (more marriage-busting allegations), Kevin Costner and Eric Clapton.

She even went on the road with some of them, including the Stones. "It was fun and emotional," she told the Italian magazine XL. "I learnt from all of them, or rather absorbed things. They are special people, these creative types, but they conquered me with the simplicity and discipline with which they work... If I hadn't learnt anything from them, I would have been no better than a groupie..."

Some critics were certainly intent on calling her that.

In 2004, her debut record of chanson, Quelqu'un m'a dit, was laughed to scorn by the French music press. But slowly it gained a word-of-mouth following before becoming a cult hit in France, Spain and Italy and even among more French-tolerant, broad-minded British music lovers, with two million sales.

Suddenly she was the new Nico - the blond model-turned-singer of the Sixties who provided an eerie, doom-laden counterpoint to Lou Reed on the Velvet Underground's records.

Despite her frank pleasure at the comparison, Carla lacks the chilly, Germanic quality of Nico. The image is of a fresh-faced mid-Atlantic folkie, somewhere between Judy Collins and Françoise Hardy; the voice capitalises on its smokiness and vagueness and even weakness, it is wispy and faint with notes suggested more than sung, and so intimate it sounds as if the microphone is halfway down her throat. As two million satisfied customers testify, it also gets under the skin.

She looks like doing it again with her second album, No Promises, released in December: her first in English, having been coached in phrasing and pronunciation by Marianne Faithfull. And the bilingual star has come up with a way of compensating for her deficiencies in English.

"When I started writing songs," she told XL, "I was immediately made aware of my mediocrity. For me songs arrive thanks to an inspiring phrase: the idea for the whole song crystallises around it. In French and even in Italian I can do it, make something substantial in this primitive fashion.

"But in English I always found myself with a third of the song missing. So I bought some books of poetry to inspire me. My friend Marianne Faithfull told me, every evening you should read a Shakespeare sonnet, you'll see how much it helps you. Instead, I fell in love with the poetry of Yeats and Emily Dickinson..." No Promises consists of songs with tunes by Carla and lyrics by Yeats, Dickinson, Auden and Dorothy Parker. It is superb, and as infectious as the first.

She has even found the man of her dreams: the French philosopher Raphaël Enthoven, 10 years her junior, father of her son, and now her husband. But before he was her husband he was somebody else's: Justine Lévy, daughter of the far more famous philosopher Bernard Henri-Lévy. In 2004 Ms Levy published a novel, Rien de Grave, which appears to be a thinly veiled, very bitter account of how Ms Bruni got her (Ms Lévy's) man.

Jerry and Justine seem to have been given ample reason to hate Carla Bruni in their time, even if they have got over it by now. Here was the woman who had it all, and then some, and then took some more. But now we learn that there is an entire back story that makes it altogether darker.

On 21 March, Sotheby's will auction 300 lots with a pre-sale estimate of up to £7.2 million. It is a unique collection of 18th- and 19th-century furniture, 18th-century paintings including portraits of royalty, politicians and socialites, and 130 miniatures, tapestries, as well as spectacular 18th-century crystal and rock crystal chandeliers. Among the highlights are what Mario Tavella, who has written the catalogue, calls "a wonderful Italian baroque giltwood table, each corner carved with allegories of each continent" and a sumptuous chandelier commissioned by the entourage of Napoleon.

These objects, and many more like them, we learn, were the things that lay about Carla Bruni in her infancy.

The Bruni Tedeschis (Carla dropped the "Tedeschi" for her professional persona) were one of the great industrial families of Piedmont. This was the north-west corner of Italy, centred on Turin, that produced unified Italy's royal family, the Savoys, and the industrial geniuses and powerhouses that transformed the peninsula from a patchwork of petty feudal states into one of the great modern nations of the world. Carla's grandfather founded CEAT in the 1920s, which became the second-most important Italian rubber company after Pirelli. The identification of "trade" and engineering with philistinism and lack of tone, so typically British, is not an Italian problem: the Agnellis, the founders of Fiat, have been social lions on account of their wealth for generations and remain so today.

Carla's father Alberto, who died in 1996, combined the industrial drive of his father with an immense musical ability and a passion for collecting. "He became an industrialist by fate," says Mario Tavella, "but chose to study music and remained a composer of contemporary music throughout his life." He sold the company in the mid-Seventies. "He also inherited his father's passion for collection," Tavella continues, "in an enormous number of fields: paintings, furniture and objets d'art, miniatures, china, handkerchiefs and even flags."

His widow Marisa, herself a concert pianist, said, "For him, going to antique shops and galleries was a passion, a game: nothing relaxed him more... He bought houses in order to fill them up with treasures, in Paris, Rambouillet, Saint-Paul-de-Vence, Cap Nègre and Rome." Not to mention Castagneto Po, the Piedmontese castle, founded in the 11th century, which Alberto bought empty in 1952 and within which he "created an 18th-century interior that has no parallel in Italy," according to Tavella. The family home.

It was an extraordinary achievement but, seen from the distance of half a century, rather a strange one: extraordinarily self-absorbed and perhaps rather suffocating, all this property, all this gorgeous stuff everywhere.

Even when Alberto went sailing, he never got away from his purchases. "His bellissimo yacht was, naturally, entirely decorated and adorned with antique maritime objects," recalls Marisa.

Life, however, gradually thrust them away from these things. In the early Seventies, when Carla was around five, the family moved to Paris to get away from the threat of kidnapping. They have since returned to Piedmont only for annual visits. And now they are divesting, selling up: if the sale is a success, Alberto's vast, eccentric patrimony will be turned into money, which will in turn be poured into a foundation the family is setting up in memory of Carla's older brother Virginio, who died after a long illness last summer, aged 46.

"It's been in their minds to sell for a few years," reports Tavella, "but the death of Marisa's son really triggered the sale. Living in such a castle surrounded by such objects is not an everyday lifestyle. Carla is a singer and her sister Valeria is an actress, and they have lifestyles that maybe are different from that of the father. And selling the collection of the father to benefit a foundation in memory of the son seems right to them."

There is a gradual paring-away of what is unnecessary, what is excessive: it's nearly a century since the pioneering modernist architect Adolf Loos declared that "ornament is crime", and now, very belatedly, even the mega-rich are beginning to fall in with the idea. Alberto had his opera house in Turin (he was the director), Marisa her grand piano; Carla has just her acoustic guitar. "I almost dress with my eyes closed now," Carla Bruni told an interviewer for this newspaper in 2004. "I never wear make-up or jewellery any more."