Marisa Meltzer’s slim biography of the British woman named Jane who became the French bag named Birkin is fittingly titled It Girl.

It is subtitled The Life and Legacy of Jane Birkin. The absurd arc of her public destiny reflects our unstoppable drift from culture to commerce. A woman whose erotic sigh-singing became a global soundtrack in 1969 is better known as the supreme trophy handbag.

“A handbag?” asks Lady Bracknell in The Importance of Being Earnest, after Jack confesses that he was a baby found at Victoria Station, in a handbag. He answers, “A somewhat large, black leather handbag, with handles to it,” which is pretty much what Jean-Louis Dumas directed his craftsmen to produce from a sketch Jane Birkin drew on the back of a vomit bag on a flight from Paris to London in 1983.

She had boarded the flight with the vast wicker basket she stubbornly carried everywhere, even to nightclubs. The kind of massive, cheap, utilitarian basket made of willow, rattan, wicker, or rush, then commonly displayed around the windows of French hardware stores. As the head of the house of Hermès, home of the Kelly bag, Dumas was appalled, and as a male, I imagine, he was eager to engage the famous, attractive woman seated next to him. He asked what kind of bag she would use instead of this basket; she sketched, and a year or so later he delivered—a somewhat large, black leather handbag with handles to it.

Birkin during the filming of Too Small My Friend, on the French seaside, 1970.

It had a mouth wide enough to swallow and release the baggage of her life: books, shoes, bottles, notebooks, clothes, receipts, Spasfon pills (for use against stomach cramps). Its top flap could be tucked inside the mouth to make room for more things. She filled it to the brim and hauled it everywhere, declaring it was “as heavy as a dead donkey,” and 10 years later donated it, scuffed and scratched, to a charity fighting AIDS.

Meanwhile, Dumas named the bag Birkin, and set about producing it for the public. The book tells us that, instead of paying for her name, Dumas thanked Jane by sending her more Birkins, which she kept selling for charity, putting luxury to good use. Eventually, Dumas started paying the charities she chose.

In 2011, she was astonished that the Birkin she auctioned for Fukushima-earthquake relief fetched $163,000. This past summer, two years and six days after her death, the original, scuffed Birkin bag that had raised money for AIDS was sold, at auction but no longer for charity, for $10 million, to the C.E.O. of a Japanese resale company with the moistly pliable name Valuence.

Birkin’s things, before and after meeting Hermès’s Jean-Louis Dumas on a flight from Paris to London in 1983.

The irony of becoming a household name as a $10 million handbag would have delighted Jane’s mother, Judy Campbell, Noël Coward’s favorite actress, who also inspired the less famous Manning Sherwin to write the wartime hit song “A Nightingale Sang in Berkeley Square.” Campbell gaily described herself, Jane, and Jane’s daughters the actors Lou Doillon and Charlotte Gainsbourg as “just like the Redgraves, except we all have different names.”

Jane’s background was solid and well connected, and like two other Parisian-British actresses, Charlotte Rampling and Kristin Scott Thomas, she had a father in uniform, a Royal Navy lieutenant commander from a wealthy Midlands family. Her great-aunt Freda Dudley Ward had been a mistress of Edward VIII’s; Freda’s daughter Penelope was married to Carol Reed, the director of The Third Man, whose gray house on the King’s Road was a landmark for cinephiles, and who told the teenage Jane that her chances of being an actress depended on whether the camera fell in love with her.

It did.

Meltzer’s biography describes what the cameras saw, and does a stalwart job of charting Jane’s progress, without access to fresh material. She used three indirect, intimate sources: Jane’s published diaries, the first ones, 1957 to 1982, initially addressed to her toy monkey, published in English as Munkey Diaries; and the later ones, 1982 to 2013, published only in French as Post-Scriptum. The third source Meltzer refers to is the up-close, playful, and sharply revealing Agnès Varda documentary Jane B. par Agnès V.

The Varda film gives us Jane’s clean candor, her British-costume-trunk appetite for make-believe, her performative unpretentiousness. She comes into true focus as Laurel opposite Varda’s Hardy. Jane’s features, you realize, are those of the sad clown; she’s Stan Laurel and herself at the same time. “Maybe that’s the job of actors,” she says, “to use what’s inside you, in the skin of someone else.” And, she says, “I want to be filmed as if I were transparent.”

She was much photographed, in two versions. In her pupal dolly-bird stage in Swinging London, she was on-screen as a naked nymphet rolling on the no-seam of the photographer’s studio in Antonioni’s Blow-Up. In life, she was on the King’s Road in the E-Type Jaguar of the cool James Bond–movie composer John Barry, his 18-year-old bride, smooth-faced and gap-toothed, with straight hair, a flat torso, and thin thighs, wearing miniskirts and crisp coats, little Twiggy lashes painted under her wide eyes. She soon gave birth to their daughter, Kate, but four months later she was a 20-year-old mother back living with her parents.

Almost immediately, Kate under her arm, Jane was in Paris for the movie Slogan, acting opposite the baggy-eyed, renegade singer-composer-drinker-night-prowler Serge Gainsbourg, 18 years her senior. It was love. He hauled Jane and the infant Kate back to his pitch-black lair, on the claustrophobically narrow Rue de Verneuil, and the provocative couple was born.

Birkin, circa 1960.

They recorded their duet “Je T’Aime … Moi Non Plus” to tell the world what they sounded like when they made love. Serge proclaimed 1969 “l’année erotique.” Shocking, a success, intermittently banned, it introduced Jane Birkin’s voice: high, soft notes delivered with halting breathiness, French words said with the uncertain open vowels of a British accent. All this is irresistible to the French, for whom the island nation represents a citadel full of under-educated virgins longing to be taught the ways of the flesh.

The visual choices were no accident. Jane had an aristo’s disregard for convention, like a duchess fixing a rip in her ball gown with a safety pin, and, like Serge, she loved to shock the bourgeoisie. The French libertine class lives by strict rules, not all borrowed from the Marquis de Sade.

“I thought breasts were necessary to please,” Jane tells Varda in the film, “but Serge likes flat-chested girls.” The flat-chested Jane wore only wife-beaters, white shirts, and washed-out men’s jeans that hung square and flat from her hips. A way of enhancing her androgyny without dressing butch, of declaring her individuality while avoiding the pretty lures and incentives of the Paris fashion world. On her feet, always, sneakers, which the British call “trainers” and the French call “baskets.”

Birkin with Gainsbourg and her daughters Kate and Charlotte, on vacation in St. Tropez.

Which brings us to the wicker basket that Jane carried to hold the diapers necessary for baby Kate, who accompanied Jane and Serge on their all-night outings. Charlotte was born in 1971, and she, too, went club-crawling. Jane left Serge in 1980 to live with the movie director Jacques Doillon, who, unlike Serge, was not a noctambule, so their baby daughter, Lou, born in 1982, went out only to lunches.

Jane Birkin was one of those generous people who give more than they get. She was in some 70 movies, recorded 20 albums, and was on the road performing almost until the end.

In 1989, after breaking up with Doillon, she lived with Lou, then seven years old, in a very Parisian little house on a sliver of courtyard between apartment buildings in Passy. She wrote with an ink pen, used a hardcover address book the size of a desk ledger, and wore those same clothes every day: faded baggy men’s jeans, sneakers, a shapeless sweater. She was 42, easing into middle age, her lids beginning to hang over her wide eyes, an actress without makeup untouched by cosmetic tweaks, easy and gentle and fun. You see her gallantry in the appetite she brought to playing the daffy, arty Mrs. Fortescue 10 years later in James Ivory’s A Soldier’s Daughter Never Cries.

Birkin with her Birkin.

When I interviewed her for Vanity Fair, she came over to the hotel room where I’d been writing to gauge exactly how messy my desk was, because she was about to play a writer in a Bertrand Tavernier film called Daddy Nostalgie.

A few weeks later, she sent me a long letter about taking daughters, rucksack, and shopping bags to mosquito-ridden Lapland, and after three pages of vivid details—“the formations are in such a rush to conceive and feed the young before dropping dead like captain Oats that they suck your blood as if there was no tomorrow”—she admitted, “I’m writing with the usual cramps about whether I’ve said anything to wound in our interview.”

She had been open, but not wounding; the rate of attrition at Vanity Fair being high, the piece never ran.

But when I watched Daddy Nostalgie again recently, I saw how perfectly she had directed Tavernier to reproduce my working mess, from the pale Olivetti Lettera 32 to the giant glass ashtray, to the dappled pattern on the hardbound notebook full of papers, to the angles at which the various papers sat, to the piles of books on the floor. She gave me the gift of my desk from 1989.

As was so often the case with the curious, generous Jane, her interlocutor came out fully seen, while she remained curiously unheard.

Joan Juliet Buck is a writer and actress and the former editor of French Vogue. You can read her Substack here