France has recorded its biggest daily rise in coronavirus infections since March, as President Emmanuel Macron raised the possibility of another nationwide lockdown.
A further 7,379 cases were confirmed on Friday, bringing the country's total to 267,077.
It was the largest daily spike since 31 March, when 7,578 cases were tallied at the peak of the first wave.
France was seeing an "exponential" rise in cases, the health ministry said.
The ministry said Friday's rise follows daily increases of 6,111 on Thursday and 5,429 on Wednesday.
Despite the sharp rise, hospital numbers and daily deaths were relatively stable, as young people less vulnerable to the disease make up most of the new infections, the ministry said.
Another 20 people were confirmed to have died with Covid-19 on Friday, bringing France's overall death toll to 30,596.
Shortly before Friday's figures were released, Mr Macron said a second national lockdown could not be ruled out if infections spiralled out of control.
However he said his government was trying to avoid the return of restrictions that would set back the country's fragile economic recovery.
"Containment is the crudest of measures to fight against a virus," said Mr Macron, urging people to be "collectively very rigorous".
France began easing its eight-week-long lockdown in May. But some parts of the country - including the capital Paris - remained under tighter controls.
Local authorities have been given powers to enforce lockdown measures, such as closing down bars and restaurants, in areas where cases are surging.
On Friday, masks were made mandatory outdoors in Paris to fight the rising infections.
How are other European countries faring?
Spain and Germany have also recorded their highest numbers of daily cases since the spring in recent days, and the World Health Organization (WHO) has warned of a resurgence of the disease in Europe.
On Thursday, Hans Kluge, the director general of the WHO's Europe office, said young people should not be complacent about the virus.
"It may be that the younger people are not necessarily going to die from it, but it's a tornado with a long tail. It's a multi-organ disease, so the virus is really attacking the lungs, but also the heart and other organs," he said.
As winter approaches, young people would also be in closer contact with older people, he said.
German Chancellor Angela Merkel warned on Friday that in the coming months things would become "even more difficult than now", as people have been able to enjoy life outdoors over the summer.
A protest against Germany's coronavirus restrictions was due to take place in Berlin on Saturday, despite a consistent rise in cases above 1,000 a day recently.
Spain, among the first European countries to see a second spike of infections, diagnosed 3,829 new cases on Friday. Ahead of the new school year, the government said school children aged six and over must wear masks to class.
Hungary announced on Friday it would close its borders to foreigners from 1 September to curb the spread of coronavirus. The country recorded 132 new infections on Friday, the highest daily number since the peak of the pandemic.
Turkey reported its highest number of deaths in 24 hours since 17 May on Friday. Another 36 people died, pushing the country's death toll to 6,245. Meanwhile, the number of daily new cases again rose above 1,500, prompting the government to impose restrictions.