"Living in this house, unconsciously perhaps it's a way of recapturing lost time in a place where we were once excluded," says Marina, who for many years struggled to accept "an inheritance given without love".
To mark the 40th anniversary of Picasso's death this year, Marina has opened up her private collection to help stage an exhibition exploring the recurrence of nudes in the great Spanish artist's work.
"Picasso, Nudity Set Free" features 120 works. Around 90 come from Marina's collection, some of which have never before been on public display.
But Marina, who was in her early twenties when her famous grandfather died, is matter-of-fact about the loan.
"This comes from my inheritance, I don't make anything special of it," she tells AFP with an air of detachment.
Marina and her elder brother Pablito's childhood was punctuated by rare and unhappy visits to see their grandfather, who spent most of his life in France.
These often featured "long waits behind the gate" while "the master" woke up, she says. Picasso's second wife "Jacqueline used to order that we wait; she rejected anything that disturbed him", Marina recalls.
Born in 1950, Marina is the daughter of Paulo Picasso, son of Picasso, and his first wife, Russian ballerina Olga Khokhlova.
Marina grew up in poverty despite her illustrious lineage and Paulo, an alcoholic, died in his fifties two years after the artist. "He was always a bit the toy of his father. He was never able to grow up," she says.
As an adult, Marina underwent years of therapy and poured her painful childhood memories into her 2001 memoir "Picasso: My Grandfather".
"At the beginning, I couldn't bear to see his paintings. It took me a lot of time to make the distinction between the artist and the grandfather," she says.
"He was not a real grandfather, or a benevolent father (to Paulo)..."
The legacy of childhood rejection took a terrible toll on Pablito.
Following Picasso's death at the age of 91 in April 1973, he swallowed bleach after Jacqueline refused him permission to see his grandfather. He died three months later.
According to Marina, "my brother wanted to embrace him for one last time and Jacqueline threw him out".
"He went home and killed himself by drinking bleach."
But if Picasso's grandchildren suffered as a result of their relationship with him, the fate of his muses — bronze busts of whom dot the villa — was equally tragic.
Marie-Therese Walter hanged herself. Jacqueline Picasso shot herself. Dora Maar suffered depression and became something of a recluse. Marina's grandmother Olga died in Cannes in 1955 unvisited by her estranged husband.
"He loved women and used them in order to be creative," she says flatly.
Four decades on, Marina has tried to overcome the bitter legacy of the past.
The Cannes house, long since renamed Pavillon de Flore, has been restored and is now filled with paintings, sculptures and ceramics by Picasso, and other artists.
Funding projects such as an orphanage in Vietnam has also helped the mother-of-five feel she has put her inheritance to good use and she now plans to turn her attention to philanthropic work in France.
With children, she says, it is what happens at the start of their lives that is the most important.
"The more that one can help (when they are) young, the better they will live later," she adds.
"Picasso, Nudity Set Free" runs until at the Centre d'art La Malmaison at Cannes.