"There is probably more than 50,000 cases per day. We estimate, on the scientific committee, that we are more in the region of 100,000 cases per day," Delfraissy told RTL radio, Reuters reported.
France, the euro zone's second-biggest economy, is currently examining whether to tighten lockdown measures further to curb the resurgence of the COVID-19 virus, having already imposed night-time curfews on major cities including Paris.
The health ministry reported on Sunday a record 52,010 new confirmed coronavirus infections over the past 24 hours, as a second wave of cases surges through Europe.
The new cases took the French total to 1,138,507, with France overtaking Argentina and Spain in registering the world's fifth-highest number of cases.
The ministry said 116 people had died from coronavirus infection in the 24 hours to Sunday, down from 137 a day earlier, taking total deaths to 34,761.