Her lawyers said the diagnosis had yet to be confirmed by further tests.
After the judge’s ruling, Bettencourt-Meyers and her two sons said they were “immensely relieved”.. Earlier the heir had warned she would leave France if any attempt to make her a ward of court was successful.
The spat, however, transformed into a political scandal after it was alleged that Bettencourt had handed over envelopes of cash to fund Nicolas Sarkozy’s presidential election campaign.
It is the first time a court has ruled that the 88-year-old is not in a fit state to manage her fortune. The decision is the latest in a family dispute between her and her daughter, Franoise Bettencourt-Meyers.
The family feud broke out four years ago when Bettencourt-Meyers claimed a society photographer, Franois-Marie Banier, had taken advantage of her mother’s frail state of mind to persuade her to hand over nearly 1bn in artworks, insurance policies and cash.
Bettencourt is to be put under the guardianship of her eldest grandson, Jean-Victor Meyers, while her fortune is placed under his and his brother Nicolas’s guardianship.
“If my daughter wins I will go abroad the worst thing, the nightmare would be to depend on Franoise,” she told a French newspaper, adding that such an eventuality might make her “lose the will to live”.
The legal decision was based on a medical report that suggested Bettencourt had dementia and moderately severe Alzheimer’s, causing disorientation as well as memory and reasoning problems, and concluded that her mental faculties were likely to deteriorate slowly.
France’s richest woman, the L’Oral heir Liliane Bettencourt, is suffering from dementia and Alzheimer’s and must be put under the guardianship of relatives, a judge in Paris has ordered.
After Monday’s legal decision, Bettencourt-Meyers appeared to try reassure investors, saying that the decision to put her mother under guardianship did not affect the cosmetics company.
The saga seemed to come to a halt a year ago when Bettencourt and her daughter signed a truce and dropped all legal action. But it was a matter of weeks before the pair were at each other’s throats again with Bettencourt warning she was ready for all out “nuclear war”.
Lawyers for Bettencourt announced they would appeal against the ruling