British tourists are to be banned from France amid concern over the rise in Omicron cases in the UK.
From Saturday morning, France is banning travel to and from the UK without "compelling reasons".
Paris says the "compelling reasons" do not include travel for tourism and business.
It added that for those able to travel from the UK under a "compelling reason", there will be the obligation to register the address of their stay in France.
Government spokesman Gabriel Attal told BFM TV the measures will include reducing the validity of pre-departure PCR tests to 24 hours from 48 for travellers arriving from Britain.
They will have to test again on arrival and isolate "in a place they choose" for at least 48 hours pending the result, Mr. Attal added.
French nationals and their spouses are exempt from the new rules.
At lunchtime, the States of Guernsey confirmed that travellers from the Bailiwick will be affected by the new restrictions.
It will also affect passengers from Jersey, the Government of Jersey has confirmed.
"Islanders planning to travel to France in the coming days and weeks are advised to consider the new restrictions, particularly in relation to essential travel reasons, before beginning their journey.
Details of the restrictions are available at the UK Government Foreign Travel advice website: Entry requirements - France travel advice - GOV.UK (www.gov.uk)."
Condor Ferries says its schedule of services over Christmas and the New Year will continue, despite the huge drop in demand that's expected as a result of this decision.
"We want to provide schedule certainty to all our passengers that our sailings are to operate over the festive period, despite the latest change in regulations.
We accept that there some Islanders may have concerns so want to reassure everyone of our commitment to maintaining connectivity with France." - Elwyn Dop, Operations Director.