As cases surge, the French Riviera shuts down and tells people to stay away.

The French Riviera, the famed strip along the Mediterranean coast that includes jet-setting hot spots like Saint-Tropez and Cannes, will be locked down over the next two weekends in an attempt to fight back a sharp spike in coronavirus infections.

France has been under a nighttime curfew since mid-January and restaurants, cafes and museums remain closed, but the government of President Emmanuel Macron has resisted putting a third national lockdown in place.

It has been a calculated gamble, with Mr. Macron hoping that he could tighten restrictions just enough to stave off a new surge of infections without resorting to the more severe rules in place in many other European countries.

The strategy has largely worked, but infection rates remain at a stubbornly high level of about 20,000 new cases per day. Officials have made it clear that the existing national restrictions would not be loosened and that more local lockdowns could be enforced in the coming days.

The French Riviera, which includes the city of Nice, has the country’s highest infection rate, and officials have grown increasingly alarmed as they surged to 600 cases per week per 100,000 residents — about three times the national rate.

“The epidemic situation has sharply deteriorated,” Bernard Gonzalez, a regional official for the Alpes-Maritimes area, said on Monday as he announced the lockdown, which will affect the coastal area between the cities of Menton and Théoule-sur-Mer.

Officials said that controls at the border with Italy, in airports and on roads would be toughened and that the police would carry out random coronavirus tests. New measures also include a closure of all larger shops and an acceleration of the vaccination campaign.

Infection rates surged as many French people flocked to the coast, attracted by the temperate Mediterranean weather as they sought to escape gloomy cities like Paris.

“We will be happy to receive lots of tourists this summer, once we win this battle,” Christian Estrosi, the mayor of Nice, said last week. “But it is better to have a period while we say ‘Do not come here, this is not the moment.’”