Mr Castex also said the government would announce new steps to tackle vaccine hesitancy next year, saying it was “not acceptable that the refusal of a few million French people to be vaccinated puts the life of an entire country at risk”.
Meanwhile, in the Netherlands, Dutch health experts have said the country should go into a “strict” lockdown, local media has reported.
Prime Minister Mark Rutte has said Omicron could be the country’s dominant strain by January, similar to France.
Since late November, bars, restaurants and most shops have been ordered to close between 17:00 and 05:00 local time. This measure was meant to end before Christmas, but will now continue until 14 January.
The Netherlands recorded more than 15,400 infections on Friday – less than previous days, but far higher overall than any other time during the pandemic.
As the Dutch healthcare system deals with an influx of Covid patients, routine care and all but urgent operations have been postponed.
The hospitality industry in the Republic of Ireland has said it will be devastated by new rules from Monday that mean pubs, restaurants, theatres and cinemas must close every night by 20:00 local time.
The move has also been criticised by some politicians from Ireland’s governing coalition, who said the new rules would encourage more gatherings in people’s homes.
Sports venues will have to operate at 50% capacity or have attendance numbers capped at 5,000. Wedding celebrations will be allowed to go on until midnight – with a maximum of 100 guests.
There is already a limit of four households allowed to socialise together inside a home.
Tánaiste (Irish deputy PM) Leo Varadkar said the government would announce financial measures on Monday to support businesses affected by the new rules.