French Riviera authorities said Sunday they are boosting security around electricity grid sites after an overnight fire in a substation that cut power to 45,000 people, and a massive blackout during the Cannes film festival blamed on sabotage.A blaze hit an electricity transformer in the western part of the city of Nice, knocking out power in the vicinity, the city’s offices of the mayor and local prosecutors said.“We strongly condemn the overnight attack against a Nice electricity transformer,” deputy mayor Anthony Borre said on X, formerly Twitter.On Saturday, a five-hour power cut disrupted the final day of the Cannes festival, knocking out traffic lights and ATMs and forcing organisers to use back-up generators. Local officials said a suspected arson attack on a substation and vandalism of an electricity pylon were the causes.“I vigorously condemn these criminal acts hitting our country,” Nice mayor Christian Estrosi said on X after the transformer blaze affecting his city.He added: “In the coming days we are reinforcing the (security camera) network around the city’s strategic electric sites.”The Nice prosecutors’ office said the substation fire occurred in the city’s Moulins district.Power was restored around dawn, said officials and the Enedis grid company.