"The goal is to avoid French citizens getting contaminated. That will be done by installing random checks at the borders," Castex told BFM TV, reiterating France's decision to keep its ski lifts closed at Christmas.
Germany and Italy share France's position but with Austria, as well as Spain and Switzerland, leaning towards opening its ski resorts, the topic has become divisive in Europe, even though Castex hinted there was still room for a agreement.
"We'll put in place ... a quarantine, meaning we will proceed with random checks at the borders and the possibility for authorities to order a seven-day quarantine", the French Prime minister said.
"But diplomacy is still in play, the die has not been completely cast (on a European ski agreement)", Castex added.
During the first wave of infections last season, some ski centres became breeding grounds for the coronavirus, accelerating its spread across Europe.