French authorities said Thursday they had confirmed the first case of the Covid-19 Omicron variant on the mainland, a man in his 50s who recently returned from Nigeria.

The ARS health agency for the Paris region said the man had not been vaccinated against the virus and showed no Covid symptoms when tested upon his arrival on November 25.

His wife, also unvaccinated, tested positive for Covid and sequencing is underway to determine if she too has the Omicron variant, and their family has been placed in quarantine, the agency said.

Previously the only confirmed Omicron case on French territory was detected on its Indian Ocean island of Reunion, though government spokesman Gabriel Attal said Wednesday that 13 suspected cases were currently being studied.

The country is facing a fifth wave of surging cases since the pandemic emerged last year, and three hospitals in northeast France have implemented emergency protocols because beds are filling rapidly with Covid patients.

Health Minister Olivier Veran has warned that average daily cases are likely to surpass the peaks of the third wave that hit last spring, possibly as soon as this week.

Starting Saturday, France will again allow in flights from southern Africa, where the Omicron variant was first reported, but permitting only French and EU residents to disembark.

They must have a Covid test upon arrival, with a negative result still requiring a seven-day quarantine, while a positive test will prompt a 10-day quarantine.