MARSEILLE, France — Since Marina Picasso was a child, living on the edge of poverty and lingering at the gates of a French villa with her father to plead for an allowance from her grandfather, Pablo Picasso, she has struggled with the burden of that artist’s towering legacy.

When she was in her 20s and inherited the 19th-century villa, La Californie, as well as a vast trove of Picasso’s art treasures, she turned the paintings to face the walls in resentment. Through 15 years of therapy, she dissected bitter family memories of her grandfather’s perceived indifference and her brother’s suicide. In her 2001 memoir, “Picasso: My Grandfather,” she bared her pain and anger at the Picasso clan.

Now 64, Ms. Picasso acknowledges that she is expanding her rebellion by preparing to sell off many of his artworks to finance and broaden her philanthropy — aid for a pediatric hospital in Vietnam and projects in France and Switzerland benefiting the elderly and troubled teenagers.

And her unconventional sales approach is reverberating through international art markets, worrying dealers and auctioneers accustomed to playing key — and lucrative — roles in the sale of renowned art. In an interview, Ms. Picasso said she would sell works privately and would judge “one by one, based on need,” how many, and which, of the remaining Picasso works, of about 10,000 that she inherited, she would put up for sale.