President Emmanuel Macron has warned French citizens to prepare for a total cut-off of Russian natural gas by supporting alternatives, having public lights switched off at night and engaging in a period of nationwide energy “sobriety”.

The Russian invasion of Ukraine and ensuing sanctions have aggravated other factors driving up prices for energy and other goods.

With no end in sight for the Ukraine war, Mr Macron said, the French should brace themselves for costs to remain high.

“This war will continue,” he said in a televised interview marking France’s national holiday, Bastille Day.

“The summer, early autumn will be very hard.”

“Russia is using energy, like it is using food, as a weapon of war,” Mr Macron said.

“We should prepare ourselves for the scenario where we have to go without all Russian gas.”

He said the government would prepare a “sobriety plan” to conserve energy, which would start with turning off public lights at night when they are not useful.

France will keep looking to diversify gas sources, the president said, calling for a faster shift towards offshore windfarms and more European cross-border energy co-operation to weather the current crisis.

Mr Macron’s political opponents on the far right and far left have blamed EU sanctions for reducing the purchasing power of French consumers while failing to persuade Russian President Vladimir Putin to pull troops out of Ukraine.

France’s president gave no indication during the interview of a policy shift towards Ukraine.

“What do you want us to do?” he asked.

“We want to stop this war without getting involved in this war. At the same time, we want to do everything so that Russia doesn’t win, so that Ukraine can defend its territory. We don’t want a world war.”