PARIS — Authorities on the Mediterranean island of Corsica are making COVID-19 tests obligatory for any visitors traveling from the French mainland for the Christmas-New Year period.

The measure is extraordinary in that it sets Corsica apart from all of mainland France’s other regions, which do not require tests for travel between them.

Under the measures announced this weekend by the French government’s top administrator for Corsica, Pascal Lelarge, all travelers aged 12 and over will need to undergo a virus test in the 72 hours before taking a plane or boat to the island. The rules will apply from Dec. 19 to Jan. 8, 2021.

Travelers will need to fill out a form confirming that they tested negative. A fine of 135 euros ($164) can be levied from travelers who don’t get tested. Lelarge also warned of possible legal action against people who infect others. Police at airports and ports in Corsica will carry out checks, and travelers will need to be able to produce paperwork from labs or pharmacists proving that they got tested.

The measures are aimed at keeping down Corsica’s infection rates, which are far lower than the national average, and to shield the island’s hospitals.