Francis Ford Coppola shrugged off the vast fortune he personally risked on his highly polarizing new film "Megalopolis", as Emma Stone and Richard Gere prepared to light up the red carpet at the Cannes Film Festival on Friday.

From "madly captivating" to "Megaflopolis", reviews have gone in every direction for Coppola's decades-in-the-making passion project a day after its world premiere on the French Cote d'Azur.

Coppola has yet to secure a US distributor for the $120 million movie for which he sold a stake in his California vineyard to self-finance.

But Coppola appeared relaxed as he faced the press on Friday.

"The money doesn't matter," said the 85-year-old director of classic movies such as "The Godfather" series.

"My children, without exception, have wonderful careers without a fortune. We are fine. It doesn't matter," he said.

Adam Driver stars as Caesar Catalina, a cape-twirling and Nobel Prize-winning architect hell-bent on using his seemingly magical powers to rebuild the collapsing urban sprawl into a utopian and futuristic Garden of Eden.

US reviews of the wildly ambitious and experimental movie were largely enthusiastic, while European outlets were markedly less convinced.

Hollywood magazine Deadline hailed its "sheer audacity", while Rolling Stone called it "a summation of a lifetime's worth of dreaming".

But The Guardian said it was "megabloated and megaboring", while France's Telerama bluntly dubbed it a "catastrophe".

Coppola -- who faced similar controversy in 1979 with "Apocalypse Now", which went on to win the Cannes top prize Palme d'Or -- said it is "the role of the artist, of films, to shine light on what's happening in the world."

"Megalopolis" takes place in New Rome, a parallel and decayed version of modern-day New York filled with bacchanalian parties, crumbling ancient statues, and chariot races.

The film opens with a warning that US democracy could fall to the whims of a few power-hungry men, as the Ancient Roman Republic once did, and it features Shia LaBeouf as a dangerous scion who embraces populist politics.

"Men like Donald Trump are not at the moment in charge but there is a trend happening in the world," Coppola warned.

"There is a trend happening towards the more neo-right, even fascist tradition, which is frightening," he said.

"Megalopolis" is one of 22 films in competition for this year's Palme d'Or.

Should his film win over a jury led by "Barbie" director Greta Gerwig, Coppola would become the first ever triple winner of the Cannes festival's top prize.

But the maestro appears ready to move on, telling journalists he has "already started writing another film."

 Stone, Gere 

 Meanwhile on Friday, Emma Stone returns to the festival fresh from her Oscar win for "Poor Things" earlier this year.

She is once again reunited with its Greek director Yorgos Lanthimos for "Kinds of Kindness".

Stone stars in one of the film's three short stories, which also feature Willem Defoe and up-and-coming actors Margaret Qualley and Hunter Shafer, the transgender star of HBO hit "Euphoria".

An icon of 20th century Hollywood is also back on the Cote d'Azur, as Richard Gere stars in "Oh, Canada", reteaming him with Paul Schrader who directed him in cult drama "American Gigolo" more than 40 years ago.

Schrader, renowned for his "Taxi Driver" and "Raging Bull" scripts, has been on a late-career run in recent years, with a series of lauded tales about tough, damaged men.

His latest, partly inspired by a near-fatal bout of Covid-19, follows a dying man haunted by his past, including his decision to dodge the Vietnam War draft.

A new Hollywood heartthrob, Jacob Elordi -- another "Euphoria" alumnus -- stars as the younger version of Gere's character.

Still to come at this year's festival are a Donald Trump biopic, "The Apprentice", and new films from arthouse favourites David Cronenberg ("The Shrouds") and Italy's Paolo Sorrentino ("Parthenope").

Films that have already screened in competition to positive reviews include Andrea Arnold's fantastical childhood portrait "Bird", and bleak period drama "The Girl with the Needle".

Cannes runs until May 25, when the Palme d'Or winner will be unveiled.