"It is with stupor that I read that my daughter thinks that my entourage has deprived me of my liberty," the 88-year-old heiress said in a letter obtained by AFP.
"It is she who is seeking to lock me up, with her actions aiming to place me under guardianship and away from those close to me," she said.
"In her request, my daughter wants to prevent me from travelling, from expressing myself freely and from living according to my wishes," she wrote.
In the latest twist to a very public family feud inside one of France's richest families, Francoise Bettencourt-Meyers this week once again asked the court to place her mother under guardianship.
Bettencourt-Meyers has argued that her mother is mentally unfit to manage France's largest private fortune estimated at €16 billion ($20 billion).
A judge in a Courbevoie court near Paris is expected to issue a ruling on the request on October 17th.
The elder Bettencourt's lawyer warned in an interview that the heiress was ready for "nuclear war" with her daughter and has asked her lawyers to revoke a reconciliation that the duo struck last year.
"I saw Liliane Bettencourt on Friday, and she is in favour of nuclear war, but we are waiting a bit before taking action," Jean-Rene Farthouat told France's Journal du Dimanche.
Bettencourt-Meyers has alleged people close to her mother, including celebrity photographer Francois-Marie Banier, took advantage of the heiress, who she claimed was no longer in a fit mental state to manage her fortune.
Banier was Bettencourt's sole named beneficiary in the will drawn up in December 2007.
But Bettencourt broke with Banier earlier this year, cutting him out of her will and depriving him of an estimated €1.25 billion.
Mother and daughter have been involved in legal battles for three years.