Jean-Luc Godard, one of the most influential filmmakers of the 20th century and the father of the French New Wave, died "peacefully at home" on Tuesday aged 91, his family said.
His legal counsel later confirmed he died by assisted suicide.
The legendary maverick blew up the conventions of cinema in the 1960s, shooting his gangster romance "Breathless" on the streets of Paris with a hand-held camera, using a shopping trolley for panning shots.
He continued to thumb his nose at Hollywood and an older generation of French filmmakers by breaking all the rules again in "Contempt" (1963) with Brigitte Bardot and "Pierrot le Fou" in 1965.
"No official (funeral) ceremony will take place," his family said.
"He will be cremated... And it really must happen in private."
Godard's legal counsel Patrick Jeanneret confirmed a report in French daily Liberation that he had died by assisted suicide.
The practice is regulated in Switzerland and permitted if offered without a selfish motive to a person with decision-making capacity to end their own suffering.
"Godard had recourse to legal assistance in Switzerland for a voluntary departure as he was stricken with 'multiple invalidating illnesses', according to the medical report," said Jeanneret.
Godard has lived as a virtual recluse for decades in the Swiss village of Rolle.
- 'National treasure' -
It was there that he died "peacefully at home", his wife Anne-Marie Mieville at his side, his producers said.
Godard's influence is hard to overestimate, with directors from Martin Scorsese, Quentin Tarantino and Paul Thomas Anderson to Robert Altman, the maker of "M*A*S*H" and "The Player", often speaking of their debt to him.
French President Emmanuel Macron hailed the director's talent and mourned the loss of a "national treasure".
"Jean-Luc Godard, the most iconoclastic filmmaker of the New Wave, invented a resolutely modern, intensely free art. We have lost a national treasure, a genius," Macron tweeted.
Figures from the film industry paid tribute to the director including Bardot who tweeted a black and white photo of the two of them walking down stairs and wrote: "By making Contempt and Breathless, Godard joined the firmament of the last great creators of stars."
American filmmaker Darren Aronofsky tweeted "thank you maestro" while actor Antonio Banderas credited the late filmmaker with "expanding the boundaries of the cinema."
British director Edgar Wright described him on Twitter as "one of the most influential, iconoclastic film-makers of them all. It was ironic that he himself revered the Hollywood studio film-making system, as perhaps no other director inspired as many people to just pick up a camera and start shooting..."
Godard's house, with green shutters and a green bench out front, had its shades drawn Tuesday, with an abandoned ashtray and teapot on the windowsill, an AFP reporter said.
Despite the filmmaker's often difficult relationship with critics, The Guardian's Peter Bradshaw heaped praise on Godard, saying, "The last great 20th-century modernist is dead".
He compared him to other 1960s rebels like John Lennon and Che Guevara.
"Or maybe Godard was the medium's Socrates, believing that an unexamined cinema was not worth having," he added.
- 'Every edit is a lie' -
Guy Lodge, of the screen bible Variety, tweeted that it was "glib to say 'he changed everything', but he sure changed a hell of a lot of things".
Indeed, Godard became a "god" to many 1960s political and artistic radicals who would hang on every word of his often contradictory -- and tongue-in-cheek -- declarations on the state of cinema and the world.
"All you need for a movie is a gun and a girl," he once proclaimed, in a nod to US actress Jean Seberg, star of "Breathless".
The movie was a fashion as well as a film landmark, her pixie haircut copied by millions bowled over by her effortless Parisian cool.
"A story should have a beginning, a middle and an end -- but not necessarily in that order," Godard later famously declared, and "every edit is a lie".
Godard would occasionally emerge from his Swiss bolthole to make low-budget films well into his 80s.
He never regained the capacity to shock or move mainstream audiences as he had in the 1960s, though a small band of disciples remained doggedly loyal to the master.
His periodic appearances at the Cannes film festival -- often via FaceTime -- still drew crowds, though he no longer held the sway he did when he had managed to shut down the festival entirely in 1968 in solidarity with the student protests in Paris.
Cannes also saw the premiere in 2017 of "Redoubtable", a tragi-comic film about Godard's doomed romance with the French actress Anne Wiazemsky, directed by the Oscar-winning director of "The Artist", Michel Hazanavicius.