A major power outage, suspected to have been a deliberate act of sabotage, threatened to jeopardise the Cannes Film Festival’s closing celebrations.

Hours before major stars were due to make an appearance, the lights went out across the French city and surrounds.

Power cuts impacted 160,000 households. Traffic lights stopped working after 10am, leading to traffic jams and confusion in city centres.

Most shops along the Croisette remained closed, and local food kiosks were only accepting cash. Train service in Cannes was also disrupted.

Screenings at the Cineum, one of the festival’s satellite venues, were briefly suspended, the festival added.

Cannes Film Festival organisers confirmed the outage affected the early activities of Saturday and said the Palais des Festivals — the Croisette’s main venue — had switched to an independent power supply.

“All scheduled events and screenings, including the Closing Ceremony, will proceed as planned and under normal conditions,” the statement said.

Power was restored hours before the much-anticipated Palme d’Or ceremony, around 3pm local time, as music began blasting again from beachfront speakers.

The end of the blackout was greeted with loud cheers from locals.

The Palme d’Or — the festival’s most prestigious prize — was later awarded Saturday night, going to Jafar Panahi’s revenge thriller It Was Just an Accident.

Other top contenders were Joachim Trier’s family drama Sentimental Value, Kleber Mendonça Filho’s political thriller The Secret Agent, and Óliver Laxe’s desert road trip Sirât.

Police said they had opened an investigation into possible arson.

The outage came hours after a fire at an electrical substation near Cannes overnight had already weakened the grid.

A high-voltage line also fell Saturday morning, electricity network operator RTE said on X.

“We are looking into the likelihood of a fire being started deliberately,” said a police spokesperson for the French national gendarmerie.

In a statement, Laurent Hottiaux, the prefect of the Alpes-Maritimes department, condemned “serious acts of damage to electrical infrastructures”

“All resources are mobilised to identify, track down, arrest and bring to justice the perpetrators of these acts,” said Hottiaux.

Iranian thriller wins Cannes’ top prize

Iranian filmmaker Jafar Panahi receives the Palme d’Or from jury president Juliette Binoche (R) and Cate Blanchett (L). Photo: AAP

It Was Just An Accident by contentious Iranian director Jafar Panahi won the Cannes Film Festival’s Palme d’Or top prize.

Panahi, who has been arrested several times for his filmmaking, was last at the festival in person in 2003, when Crimson Gold was screened in the Un Certain Regard category.

“Art mobilises the creative energy of the most precious, most alive part of us. A force that transforms darkness into forgiveness, hope and new life,” said jury president Juliette Binoche when announcing the award on Saturday

It Was Just An Accident follows Vahid, played by Vahid Mobasseri, who kidnaps a man with a false leg who looks just like the one who tortured him in prison and ruined his life.

Vahid sets out to verify with other prison survivors that it is indeed their torturer, and then decide what to do with him.

The Grand Prix, the second-highest prize after the Palme d’Or, was awarded to Sentimental Value from acclaimed director Joachim Trier.

Twenty-two films in total were competing for the prize at the 78th Cannes Film Festival, with entries from well-known directors Richard Linklater, Wes Anderson and Belgium’s Dardenne brothers.

-with AAP