The number of vaccines France is set to have access to is "more than we need," said Castex, adding it was a "question of weeks" until the first orders arrived.
France will roll out its vaccine plan "very soon" and jabs will be free for everyone, prime minister Jean Castex announced on Thursday.
Thanks to contracts at EU level, France could potentially access 200 million vaccine doses, which would be enough to vaccinate 100 million people, as two injections are currently needed a few weeks apart.
This amount is "more than we need," said Castex, adding it was a "question of weeks" until the first orders arrived.
France has a population of around 66 million.
France will roll out a three-phased strategy that will kick off with 1 million priority citizens being vaccinated in January, starting with elderly people in care homes and some staff in the establishments.
The next phase will last from February to spring and the second group of people that will receive the injections are those considered at risk because of their health or age, as well as certain healthcare professionals.
The final stage will be to vaccinate the rest of the population, the prime minister said.
He emphasised that France would wait for EU authorisation of the two vaccines nearest delivery, the Moderna and Pfizer candidates, adding that the country wanted to avoid the logic of a "first come first served" approach in its vaccine strategy.
The politician said that logistical requirements surrounding the practical aspects of vaccines, such as the Pfizer/BioNTech jab that needs to be kept at -70C, are "very complex" but that France stands ready as soon as the first doses are delivered to get them to citizens that need them.
Castex painted a more positive picture of the coronavirus situation across the country, saying it was improving progressively, with that rates of the infection were going down and the burden on hospitals easing.
The number of infections in France was set to pass under the 10,000 mark in the coming days, which the prime minister attributed to the curfew and strict national lockdown measures over the last few months.
But he urged caution, saying rates are still higher than in May and that people should keep in mind over the festive period that there could be a resurgence in the virus, like after the summer.
He said while the government had announced a relaxing of rules over Christmas and New Year "we can't celebrate as we would before" and that people needed to respect social distancing measures and stick to six adults at gatherings.