French rugby clubs are being urged by the government to postpone matches against British sides to lower the risk of being infected by a more contagious variant of the coronavirus.
The move casts doubt on the ongoing European Champions Cup and second-tier Challenge Cup, and the Six Nations starting in February.
The variant has put unprecedented strain on Britain's hospitals and forced a third national lockdown.
After European Challenge Cup matches in Britain at the end of December, several players in French teams Bayonne and Pau tested positive.
"The sports ministry is writing this weekend to the National Rugby League (LNR) to ask it to postpone the next matches involving French clubs, in accordance with the wishes expressed by several professional French rugby clubs over the last few days," the health ministry said in a statement on Saturday.
"Furthermore, the sports minister has started a census of all the sporting events scheduled in the next few weeks involving participants from the United Kingdom."
A meeting on Monday involving the sports ministry, the LNR — which runs the Top 14 — and other French sports federations will discuss their competitions involving British clubs.
The Champions Cup and Challenge Cup are in the group stage, having played two rounds with two more to go.
In the Champions Cup, Toulon is scheduled to host Welsh side Scarlets next Friday, and Lyon is home to Scottish team Glasgow Warriors on Saturday.
In the Challenge Cup next weekend, Pau is hosting London Irish, and Bayonne is to go to Leicester Tigers.
"The health situation in the United Kingdom with the spread of the variant at European level is worrying," the ministry said. "That's why any trip or stay in the United Kingdom is strongly not advised."
A separate meeting will be held with regards to the Six Nations. No further details on that meeting have yet been provided. France starts in Rome on Feb. 6, faces Ireland in Dublin on Feb. 14, then hosts Scotland on Feb. 28.