The Foreign Office has warned British holidaymakers travelling to France to expect possible fuel shortages.
Protesters are continuing their nationwide blockade of oil refineries amid a bitter dispute with the government over labour reforms.
Updating its travel advice, the Foreign Office said:
The stand-off between France's government and the union intensified on Wednesday as the country mobilised strategic oil stocks for the first time in six years.
A depot blockade was broken by police firing water cannons as the CGT called a strike at a nuclear plant, escalating fears that the industrial action could disrupt the Euro 2016.
CGT chief Philippe Martinez, said his union would press on with its strikes and a blockade in Donges set to continue until Sunday.
Unions have carried out the strikes over fears that labour market reforms could make it easier for firms to hire and fire with fewer regulations.