French student Antoine, 23, had to rush back to Bristol, where he is at university, cutting short his summer holidays.
"I'm a waiter in a small cafe near college, I can't afford to spend 14 days in the house," he said at London's St Pancras railway station after getting off a Eurostar train.
"I was supposed to come back on Monday morning, but as soon as I heard the news I rushed to the Eurostar app to change my ticket -$148 more than my original ticket."
Britain's badly-hit tourism sector also criticised the move.
"The UK needs a more sustainable long-term plan for the resumption of travel than quarantine roulette," said a spokesperson for Heathrow Airport, the country's busiest hub.
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On Thursday France recorded 2 669 new coronavirus infections, its highest daily number since May.
For months Britain had no quarantine measures but in June imposed a blanket self-isolation requirement on all people arriving.
Weeks later it carved out "travel corridors" which exempted travellers arriving from certain countries from quarantine.
However, the measures were reintroduced for arrivals from Spain in late July, catching airlines by surprise - as well as thousands of Britons leaving for their holidays.
Britain then reimposed quarantine for travellers from Andorra, Belgium and the Bahamas last week.
Scientists at Britain's Joint Biosecurity Centre advised the latest measures be taken after France's cases per 100 000 population rose above 20.
"France is heading in the wrong direction... we have to act," Shapps told the BBC on Friday.
With more than 41 000 deaths caused by the Covid-19 disease, Britain is the worst-hit country in Europe and Prime Minister Boris Johnson has been criticised over his handling of the crisis.
His government announced late Thursday that casinos and bowling alleys will be allowed to reopen in England after being shut during the lockdown, but that those not wearing masks face harsher fines.
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Skating rinks can also reopen and pilot schemes of larger crowds at sporting events will be introduced following a two-week delay to the initial plans caused by a spike in cases.
Johnson said "concerns" about increasing cases two weeks ago had dissipated after growth "levelled off" - although more than 1 000 people a day are still testing positive.
Indoor theatres, music and performance venues will be able to reopen with socially distanced audiences.
"However, as I have always said, we will not hesitate to put on the brakes if required," the prime minister warned.
The government also announced that the fine for those who "repeatedly flout face covering rules" will be doubled to a maximum of $4 200, alongside penalties for "people hosting raves or other unlawful gatherings of more than 30 people".