A second power outage in two days his hit the French Riviera region after a fire at a substation in Nice overnight, which authorities said was caused by a malicious act.

At least 45,000 homes were affected after the blaze broke out at around 02:00 local time (01:00 BST) on Sunday, a day after nearby Cannes suffered a massive blackout that was blamed on suspected sabotage.

Police in Nice say “tire tracks” were found and the door to the substation, in the west of the city, was “broken”, according to local media reports.

Nice Airport, the tramway network, and neighbouring towns of Saint-Laurent-du-Var and Cagnes-sur-Mer, were impacted before power was restored later in the morning.

Nice’s mayor Christian Estrosi said on X that he “strongly denounced” the “malicious acts that affect our country”.

The city’s deputy mayor, Gaël Nofri, said the substation fire was “probably of criminal origin”.

It came a day after Cannes suffered a major blackout during the international film festival. Officials said it may have been caused by an arson attack on a substation.

Around 160,000 homes in the city and surrounding areas lost power.

Several screenings were interrupted by the power cut in the morning, before festival organisers were able to switch to private generators.

At the moment, no link has been established between the two incidents.

Estrosi said authorities would reinforce the security network around the Nice’s electric sites. An investigation into “organised arson” has been opened.

Nice prosecutor Damien Martinelli was quoted by AFP news agency as saying investigations were underway, in particular “to clarify the damage and the manner in which the act was committed”.