A jury led by Greta Gerwig prepared to crown the winner of the Palme d'Or at the Cannes Film Festival on Saturday after a politically charged 77th edition packed with blood, sex and powerful feminist messages.

The closing ceremony got underway at the world-renowned festival on the French Riviera with the jury set to announce winners from the 22 entries in the main competition.

Iranian director Mohammad Rasoulof emerged as a late front-runner for the festival's top prize after his powerful drama "The Seed of the Sacred Fig" about his country's "Women, Life, Freedom" protests premiered on Friday.

Rasoulof fled a lengthy prison sentence in his home country just days before last week's festival started.

"The Iranian regime... is in a panic that our stories will be told. It's absurd," Rasoulof told reporters at the festival on Saturday.

Attention now turns to the jury led by "Barbie" director Gerwig, which includes the actors Omar Sy and Eva Green.

"Star Wars" creator George Lucas walked the red carpet as he prepared to receive an honorary Palme d'Or.

Among the favourites for awards is a highly original musical about a Mexican narco boss having a sex change, "Emilia Perez", by French director Jacques Audiard.

Its title star Karla Sofia Gascon would be the first trans winner of an acting prize at Cannes.

Critics also loved "Anora" by US indie director Sean Baker, a raw and often hilarious story about a New York erotic dancer who strikes gold with a wealthy client, only to face the wrath of his Russian oligarch parents.

Another favourite for the acting prize is Demi Moore after rave reviews for her "fearless" performance in "The Substance", an ultra-gory horror film about the pressures women face to maintain bodily perfection as they age.

Directing legend Francis Ford Coppola was spotted at the festival early Saturday, suggesting he may pick up an award later for his Ancient Roman fable "Megalopolis".

Anticipation was sky-high before the festival for his decades-in-the-making epic: Could he recreate the 1970s magic of "The Godfather" and "Apocalypse Now", for which he twice won the Palme d'Or?

Critics were deeply divided over whether it was a profound end-of-life philosophical statement or an incomprehensible mess.

 'Powerful indictment' 

 There was a notable paucity of meaty roles for men this year.

Many expect Ben Whishaw -- one of Britain's best character actors, and the voice of Paddington Bear in the popular family films -- to take the prize for "Limonov: The Ballad", in which he plays a dissident Soviet poet.

One of the few other standouts was Sebastian Stan as Donald Trump in "The Apprentice", a surprisingly nuanced biopic about the former US president's formative years.

Trump's team called it "garbage" and vowed to sue over its depiction of him raping his wife.

A late dark horse is "All We Imagine as Light", the first Indian entry in 30 years.

It is a poetic monsoon-set portrayal of two nurses who have migrated to Mumbai, described as a dreamlike five-star "triumph" by The Guardian.

It seems almost guaranteed that Rasoulof will get some sort of prize for "The Seed of the Sacred Fig".

Critics described it as a "deeply upsetting masterwork" (IndieWire) and a "powerful indictment of Iranian oppression" (The Hollywood Reporter).