The number of new cases was already significantly higher than during the first wave, which drags the country into "a difficult, even critical situation", Xinhua news agency quoted Jean-Francois Delfraissy, head of the scientific council that advises the government on the pandemic, as saying on Monday.
"We have anticipated a second wave. However, we are surprised by the brutality of what has been happening over the past 10 days," he told RTL radio.
"There are probably more than 50,000 cases per day, it is estimated by the scientific council that we are rather around 100,000 cases per day," Delfraissy added.
On Sunday,
Sunday's figure came after the previous day's record of 45,422 cases, according to the Public Health Agency.
Since the beginning of the pandemic, France has so far registered a total of 1,209,651 cases, while the death toll stood at 35,052.
Seventeen per cent of the tests were positive on Monday, up from 16 per cent on October 24, 15.1 per cent a day earlier, and just 4.5 per cent in early September.
Citing the steep increase in infection rates, Eric Caumes, head of the Infectious Diseases Department of Pitie-Salpetriere hospital in Paris, said: "I think that today we no longer have a choice, we will have to re-confine... There will be no other solution, unfortunately.
"We will no longer be able to properly treat other patients if the system is saturated with Covid-19 patients. The longer we wait to make the right decisions, the less effective they will be."
According to Karine Lacombe, head of the Infectious Diseases Department at Saint-Antoine Hospital in Paris, "the situation is now out of control.
"We will see how the healthcare system will resist till the weekend. But as it stands, a lockdown will probably be the measure that will have the biggest impact on the saturation of the sanitary system," she said.
The government has pledged to avoid an expensive lockdown, which curbed the first wave of the outbreak at the cost of an unprecedented economic recession.
Since September, extra anti-pandemic measures have been implemented in regions on maximum alert.
The government has introduced night-time curfews in 54 departments, affecting more than two-thirds of France's 67 million people.
As of 12 midnight from October 23 until early December, people must stay at home between 9 p.m. and 6 a.m.
"If we completely re-confine as we did in March, it is not a 10 per cent recession what we risk but a collapse of the economy," warned Geoffroy Roux de Bezieux, president of MEDEF, France's main employers' organization.
"When we were locked down in March, we had a growing economy, companies had healthy finances. Now, they are weakened and risk to not recover," he said, noting the need to "find the right level of restriction that allows the economy to continue."
Delfraissy believes that the second scenario is "to go directly towards confinement, less hard than that of the month of March" and "for a shorter duration followed by very specific deconfinement conditions".
"The faster we take measures, the more (they) will have a certain form of effectiveness," he added.