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PARIS, Sept 21 (Reuters) - French businesswoman and billionaire Liliane Bettencourt, whose family founded L'Oreal and still owns the largest stake in the cosmetics giant, has died aged 94, her daughter said on Thursday.
Bettencourt, listed by Forbes as the world's richest woman, was the heiress to the beauty and comestics company her father founded a century ago as a maker of hair dye.
Her death opens a new phase for L'Oreal, France's fourth-largest listed company, altering the relationship it has with key shareholder Nestle, the Swiss food company.
Bettencourt and her children owned 33 percent of the company. Her daughter Françoise Bettencourt-Meyers said in a statement the family remained committed to L'Oreal and its management team.
"My mother left peacefully," Bettencourt-Meyers said, adding that she had died during Wednesday night at her home in Paris.
"I would like to reiterate, on behalf of our family, our entire commitment and loyalty to L'Oreal and to renew my confidence in its President Jean-Paul Agon and his teams worldwide."
Agon was appointed chairman and chief executive of L'Oreal in 2011.
Nestle, which owns a little over 23 percent of L'Oreal, had an agreement with the founding family stipulating that the two parties could not increase their stakes in the cosmetics group during Liliane Bettencourt's lifetime and for at least six months after her death.
The Swiss company has been a major investor since 1974, when Bettencourt entrusted nearly half of her own stake in the firm to Nestle in exchange for a three percent holding in the Swiss company. She took the move out of fear that L'Oreal might be nationalised if the Socialists came to power in France.
Activist hedge fund Third Point recently urged Nestle to sell down its stake.
A Nestle spokeswoman on Thursday did not comment on the company's stake, only saying: "It's time to send our sincere condolences to Madame Bettencourt's family."
Bettencourt's net worth was estimated at $39.5 billion earlier this year by Forbes, making her the world's richest woman and among the 20 wealthiest people in the world.
She had been under the guardianship of family members since a court fight - known as the "Bettencourt affair" - ended with a ruling in 2011 that she was incapable of looking after her fortune because she suffered from dementia and had been exploited.
The case, which dogged the heiress for years, centred on Francois-Marie Banier, a celebrity photographer who befriended Bettencourt in the 1980s and received lavish gifts from her, including life insurance policies worth $400 million.
Another strand of the sprawling case involved allegations of illegal payments by Bettencourt to members of the French government associated with former president Nicolas Sarkozy in 2010. Sarkozy was eventually cleared in the case.
Paris-born Bettencourt joined her father Eugene Schueller's firm as an apprentice at the age of 15, mixing cosmetics and labelling bottles of shampoo.
She married French politician Andre Bettencourt in 1950 and inherited the family fortune when her father died in 1957.
For an obituary, please see (Reporting by Matthias Blamont, Dominique Vidalon, Martinne Geller and Luke Baker; Writing by Sarah White; Editing by Andrew Roche)