A 6pm curfew is to be introduced nationwide in France, starting Saturday.
Prime Minister Jean Castex said the measure will remain in force for at least two weeks.
Up to now, most of France has been under an 8pm curfew, with some parts of the country, especially in the hard-hit east, already under the stricter 6pm curfew.
Mr Castex said a much-feared infection surge following the year-end holidays had not happened, but said a new lockdown could be imposed "without delay" if the health situation were to deteriorate badly.
The situation in France is "under control", he said, but still "fragile".
Schools will remain open, but indoor sports activities have again been banned for now.
Mr Castex also said that travellers arriving in France from non-European Union destinations would have to present a negative Covid test less than 72 hours old, and would have to self-isolate for seven days. They would then have to take a second test.
Bringing it forward by two hours would stall the "apero effect", the leader of President Emmanuel Macron's Republic on the Move party, Stanislas Guerini, said earlier in reference to the French tradition of meeting up for a pre-dinner aperitif.
France on Wednesday recorded around 23,000 new cases of Covid-19, around half the number detected in Britain on the same day but still far above the 5,000 figure the government had been aiming for by mid-December.
Speaking during a visit to a vaccination centre in the north-eastern city of Metz on Thursday, Mr Castex noted with satisfaction that vaccine scepticism was starting to decline.
He predicted a "stampede" for the injections among over-75s.
However, French data privacy watchdog CNIL condemned the Interior Ministry for the use of drones to oversee demonstrations and make sure people were respecting the Covid-19 lockdown.
In a decision made public on Thursday, the authority stressed that the use of such tools by the police nationwide broke the law in the absence of any regulatory framework.
Meanwhile, Germany's public health chief said the country will have the coronavirus pandemic under control by the end of the year.
However, he warned that a new, fast-spreading strain of the virus risks exacerbating the situation.
Germany has so far recorded 16 cases of people with a strain of the virus first detected in Britain and four with the strain from South Africa, Lothar Wieler, president of the Robert Koch health institute, told a news conference. All cases so far were people who had travelled abroad, he said.
These will not be the last variations to be seen, he said, also referring to a new coronavirus variant found in Brazil.
"We will have more variations ... Therefore, don't travel."
Mr Wieler urged people who were offered a Covid-19 vaccination to accept it to relieve the strain on hospitals and said people should stick to social distance and hygiene rules.
"At the end of the year we will have this pandemic under control," Mr Wieler said. Enough vaccines would then be available to inoculate the entire population, he said.
Mr Wieler said restrictions were not being implemented as consistently as they were during the first wave and said more people should work from home.
He pointed to the sharp spike in infections seen in Ireland in recent days as an example of how quickly an outbreak can escalate again if rules are relaxed, especially given the new seemingly more contagious variant of the virus circulating there and in neighbouring Britain.
At the Vatican, both Pope Francis and his predecessor, former pope Benedict XVI, have received the coronavirus vaccine.
The Argentine pontiff, 84, has previously spoken of the importance of the jab in the fight against Covid-19, which has severely curtailed his own love of being among his flock.
In an interview broadcast at the weekend, Francis urged people to get the vaccine.
"There is a suicidal denial which I cannot explain, but today we have to get vaccinated," he told Canale 5.
Meanwhile, in the UK, police officers and firefighters are being trained to drive ambulances to assist the stricken paramedic service. The UK suffered its highest daily death toll of the pandemic on Wednesday, at 1,564, and the country's hospitals are moving closer to breaking point.
A record 4.5 million people in England were awaiting non-urgent hospital treatment in November and the number waiting for more than a year has soared, figures showed, underscoring the pressures on hospitals swamped by the Covid-19 crisis.
"These figures are a stark reminder that the NHS is facing an exceptionally tough challenge," said Stephen Powis, national medical director with the National Health Service.
"While still millions of people are getting care for non-Covid health problems... there is no doubt that services will continue to be under additional pressure until and unless this virus is under control."
