The British government made it clear it still requires fully vaccinated travellers from France – whether they are UK residents returning from a holiday or people vaccinated in France – to undergo 10 days of quarantine after arrival. But what about fully vaccinated travellers from Italy, Spain or Germany for example who are just driving through France to get to the UK? It also wasn’t clear whether there were exceptions for those air passengers travelling to the UK via a French airport. It's cheaper to have an extra booking, that 2 extra tests and min 5 days quarantine. — Tom (@HeyTomBeck) July 29, 2021So it would seem that fully vaccinated travellers heading to the UK from a European country would be best off not going via France if possible.

Source: The Local July 30, 2021 07:18 UTC