PARIS — France is tightening its vaccination rules in a way that could put Novak Djokovic at risk of missing the French Open.

From Feb. 15, anyone who is not vaccinated against the coronavirus will need to show proof they tested positive for COVID-19 within the previous four months – down from the current six-month window – in order to enter sports venues in France.

The French law is central to the government’s plan for tackling the virus and aims to bar unvaccinated individuals from stadiums, restaurants, bars and other public places.

Djokovic, who is not vaccinated, said he tested positive in mid-December. Under the current rules with a six-month window, he could play in the French Open, which starts May 22. But if the new requirements stay in force until then, they are likely to rule him out unless he gets vaccinated or tests positive again within four months of the start of the clay-court Grand Slam.

The top-ranked Djokovic is the defending champion in Paris. Earlier this month, he was deported from Australia and barred from playing in the Australian Open for not meeting the country’s strict COVID-19 vaccination rules.

French Open organizers have previously said it’s too early to comment since virus restrictions can change between now and May depending on the situation.

Djokovic was granted an exemption to Australia’s strict vaccination rules by two medical panels and the tournament organizer in order to play in the Australian Open based on documents he supplied showing he had recently had COVID-19. He received a visa to enter the country through an automated process. But upon arrival, border officials said the exemption was not valid and moved to deport him.

In the end, Australian authorities revoked Djokovic’s visa, saying his presence could stir up anti-vaccine sentiment and that kicking him out was necessary to keep Australians safe. He was deported a day before the tournament got underway in Melbourne.