Bardot died on Sunday at her home in southern France, according to Bruno Jacquelin, of the Brigitte Bardot Foundation for the protection of animals.
Speaking to The Associated Press, he gave no cause of death, and said that no arrangements had been made for funeral or memorial services. She had been hospitalised last month.
Bardot became an international celebrity as a sexualised teen bride in the 1956 movie And God Created Woman. Directed by then husband Roger Vadim, it triggered a scandal with scenes of the long-legged beauty dancing on tables naked.
At the height of a cinema career that spanned more than two dozen films and three marriages, Bardot came to symbolise a nation bursting out of bourgeois respectability. Her tousled, blond hair, voluptuous figure and pouty irreverence made her one of France's best-known stars, even as she struggled with depression.
Such was her widespread appeal that in 1969 her features were chosen to be the model for Marianne, the national emblem of France and the official Gallic seal. Bardot's face appeared on statues, postage stamps and coins.
''We are mourning a legend," French President Emmanuel Macron said in an X post.
Bardot's second career as an animal rights activist was equally sensational. She traveled to the Arctic to blow the whistle on the slaughter of baby seals. She also condemned the use of animals in laboratory experiments, and she opposed Muslim slaughter rituals.
"Man is an insatiable predator," Bardot told The Associated Press on her 73rd birthday, in 2007.
"I don't care about my past glory. That means nothing in the face of an animal that suffers, since it has no power, no words to defend itself."
Her activism earned her compatriots' respect and, in 1985, she was awarded the Legion of Honor, the nation's highest recognition.
Later, however, she fell from public grace as her animal protection diatribes took on a decidedly extremist tone. She frequently decried the influx of immigrants into France, especially Muslims.
She was convicted and fined five times in French courts of inciting racial hatred, in incidents inspired by her opposition to the Muslim practice of
In 2018, at the height of the #MeToo movement, Bardot said in an interview that most actors protesting sexual harassment in the film industry were "hypocritical," because many played "the teases" with producers to land parts.
She said she had never had been a victim of sexual harassment and found it "charming to be told that I was beautiful or that I had a nice little ass."
Among Bardot's films were A Parisian (1957); In Case of Misfortune, in which she starred in 1958 with screen legend Jean Gabin; The Truth (1960); Private Life (1962); A Ravishing Idiot (1964); Shalako (1968); Women (1969); The Bear And The Doll (1970); Rum Boulevard (1971); and Don Juan (1973).
But, while a popular star, her girlish pout, tiny waist and generous bust were often more appreciated than her talent.
"It's an embarrassment to have acted so badly," Bardot said of her early films.
With the exception of 1963's critically acclaimed Contempt, Bardot's films were rarely complicated by plots. Often they were vehicles to display Bardot in scanty dresses or frolicking nude in the sun.
"It was never a great passion of mine," she said of filmmaking.
"And it can be deadly sometimes. Marilyn (Monroe) perished because of it."
Bardot retired to her Riviera villa in St Tropez at the age of 39 in 1973 after The Woman Grabber. As fans brought flowers to her home Sunday, the local St Tropez administration called for "respect for the privacy of her family and the serenity of the places where she lived."
