French President Emmanuel Macron has announced a second national lockdown for at least the whole of November.
Mr Macron said under the new measures, starting on Friday, people would only be allowed to leave home for essential work or medical reasons.
Non-essential businesses, such as restaurants and bars, will close, but schools and factories will remain open.
Covid daily deaths in France are at the highest level since April. On Tuesday, 33,000 new cases were confirmed.
Mr Macron said the country risked being “overwhelmed by a second wave that no doubt will be harder than the first”.
Earlier, German Chancellor Angela Merkel said her country must “act now” and called for a “major national effort” to fight the spread of coronavirus.
Infections are rising sharply in many European countries.
Night curfews are in force in several countries, including for 46 million people in France. However, one minister has complained that they have failed to halt social interactions.
What’s the latest from France?
Addressing the nation on Wednesday, Mr Macron said that France must now “apply the brakes brutality” to avoid being “submerged by the acceleration of the epidemic”.
He said that half of all in intensive care beds at French hospitals were being occupied by Covid patients.
The president said that under the new rules, people would need to fill in a form to justify leaving their homes, as was required in the initial lockdown in March. Social gatherings are banned.
“Like in the spring, you will be able to leave your house only to work, for a medical appointment, to provide assistance to a relative, to shop for essential goods or to get some air near your house,” Mr Macron said.
Citizens would be allocated one hour for exercise and would only be permitted to travel for work if their employer deemed it impossible for them to work from home.
Mr Macron added that visits to care homes – which were banned during the two-month lockdown declared in March – would be permitted under the latest measures.
The curbs will apply until 1 December and will be reassessed every two weeks. The president said he retained “hope that families will be able to be reunited for Christmas”.