De Brunhoff suffered a stroke Saturday night and died Monday in a hospital in Paris, where she lived, said Mathieu de Brunhoff, one of her sons.
She first invented the tale of a little elephant as a bedtime story for her boys in 1931. They in turn told their father, painter Jean de Brunhoff, who illustrated the story and filled in details, naming the elephant Babar and creating Celeste, Zephir and the "Old Lady," who takes care of young Babar after his mother is killed.
"For children, a story of an elephant who has so many adventures in such a short time is really something that is so enchanting," the son, Mathieu, said Tuesday in a telephone interview.
"With the paintings of my father, paintings that were so marvelous, it was a great combination," he said.
Before "The Story of Babar" was published, Cecile de Brunhoff insisted that her name be removed from the book because she thought her role too minor, according to publishers Harry N. Abrams Inc.
"She was very modest," said Mathieu.
A pianist, she was a graduate of the prestigious Paris music college, the Ecole Normale de Musique.
Jean de Brunhoff died of tuberculosis in 1937, aged 37. His eldest son, Laurent, carried on Babar's adventures, completing two books unfinished by his father and eventually devoting himself full-time to Babar, publishing dozens of books of his own.
Cecile de Brunhoff, who was born Oct. 16, 1903, and did not remarry after her husband's death, is survived by her three sons, four grandchildren and four great-grandchildren, said Mathieu. He said the family would hold a private funeral outside of Paris.