Agnès Varda in the courtyard of her Paris home

No one who attended her Patutopia video-installation at the Venice Biennale in 2003 will ever forget the sight of Agnès Varda – the grandmother of the French New Wave – hailing well-wishers dressed as a potato.

This hallmark playfulness and lack of pretension makes a welcome return in Varda’s latest film, Les plages d’Agnès (The Beaches of Agnès), in which the 81-year-old filmmaker looks back over an eventful life. A big critical success on its release in France over a year ago, Les plages sold more than 250,000 tickets and earned Varda this year’s César for best documentary.

“Pick it up,” says Varda, pointing to a bronze statue on the windowsill of her dining room in Paris. “Now pick up the one next to it,” she adds, motioning to her 1982 César for best short documentary. “You see,” she says gleefully, “this new one is much lighter.”

The rest of Varda’s trophies, including her Venice Golden Lion for 1985’s Sans toit ni loi (Vagabond) starring Sandrine Bonnaire, and those of her late husband, the filmmaker Jacques Demy, are discreetly shut away in a corner cabinet. Much more prominent are the numerous framed photographs of heart-shaped potatoes she took while making her 2000 documentary Les glaneurs et la ganeuse (The Gleaners and I) about the intelligence of gleaning in a wasteful world.

“I was making a statement about how everything is so formated nowadays, potatoes have to be just so, apples too,” says Varda, her hair cut in a resplendent two-tone bob. “I thought this was an interesting metaphor for our society which likes people to be formated, something I’ve never wanted to be as a filmmaker. I know I’m working on the margins and that’s what I like to fight for: alternative cinema.”

Varda prefers to describe Les plages not as a documentary but as “an unidentifiable filmic object”. “I had to introduce some elements of fiction,” she says. “My courtyard which you saw as you arrived; it looks like a dream-place to have in Paris, so full of flowers, but when I moved in here over 50 years ago it was a complete mess; to evoke that I had to make a set in the studio with a fake courtyard, all dirty.”

Throughout her career as a filmmaker, starting with her debut La pointe-courte (1954), Varda has looked for ways to innovate. For La pointe-courte, set in the French fishing village of Sète where she lived as a teenager, Varda was one of the first New Wave auteurs to have professional and non-professional actors perform alongside each other.

“I love filming real people; I love to connect with the kind of people we don’t know so well,” she says. Varda’s inspiration for her most popular film, Vagabond, which sold over a million tickets in France, were the young women she saw taking to the roads in the early 1980s.

“Before it was only men,” she says. “I was fascinated by these unwashed young women, with just a pack on their pack, rebelling against everything, mad at everyone. I made the film to capture a new phenomenon.”

More recently, Varda has embraced digital technology and making documentaries where she inserts herself into the film: “The Gleaners was quite radical because I was making a documentary about a serious subject, but not trying to come across like a sociologist or an ethnologist, but remain in a way vaguely futile, loving my cats, or discussing a wonderful oil painting by Jean-François Millet. My life is my work and if my life can enter into my work then I embrace that.”

The daughter of a Greek father and a French mother, Varda grew up in Belgium before fleeing to France with her family in 1940. After studying photography at the Beaux Arts in Paris, she began working as a photographer for France’s Théâtre Nationale Populaire, under the aegis of Jean Vilar. It was with very little knowledge of films or filmmaking that she directed La pointe-courte, producing it through her own company Ciné Tamaris, which is still going strong today.

“I didn’t grow up watching films,” Varda says. “I’d seen Les enfants du paradis twice, which I loved, but very little else. It was quite liberating because I felt free to make films the way I wanted to make them. If I’d watched film masterpieces growing up then perhaps I wouldn’t have dared become a filmmaker.”

Varda’s idea for Les plages d’Agnès came to her one day on a beach in Noirmoutier, an island off the Vendée coast of western France, where she holidayed as a child. “If you opened people up, you would find landscapes,” she says in her film. “If you opened me up, you would find beaches.” It is a beautiful conceit that finds expression not only on the beaches of Belgium and France but on the streets of Paris, where she creates an artificial beach, and Venice Beach in Los Angeles, where she spent two heady years from 1968-1970.

“It’s ridiculous in a way to make a film about yourself,” says Varda. “What encouraged me was reading something wise Montaigne wrote in the introduction to his Essais. After years of writing philosophy, this very serious old man decided it was time he wrote something about his own life so that when he died his friends and family would know what kind of a man he was.”

Varda hopes that by telling her story, “it will help people believe they can cope with their own lives”. In Les plages she opens up for the first time about the death of her husband Jacques Demy, the director of musicals such as Les parapluies de Cherbourg (1964) and Les demoiselles de Rochefort (1967), who succumbed to Aids in 1990.

Varda’s final gift to her husband was to direct Demy’s screenplay Jacquot de Nantes, about his childhood in that French city. “I thought it would be interesting in Les plages to talk to some of the people who helped make Jacquot de Nantes and were with us when Jacques was dying,” says Varda. “None of us, his family nor the crew, had the right to speak about something he [Demy] did not want to speak about. The thing is that he died, he could have died from cancer, it would have been just as painful, and missing him is a part of the film, I guess.”

A consolation and a massive part of Varda’s work since her husband’s passing has been to restore and transfer Demy’s films from their original negatives on to DVD. Varda and Demy’s children, the costume designer Rosalie Varda and the actor Mathieu Demy, have been aiding her in this task. “I’m so happy that my children now use their own talents to transmit the beautiful work of Jacques Demy,” Varda says. “It goes through them now which makes me feel good about them and good about Jacques.”

‘Les plages d’Agnès’ is released in the UK on October 2