Most French fuel forecourts are suffering shortages, the RAC is warning.
The motoring organisation has advised Britons setting their to destinations across the Channel to stock up before heading off.
An industrial row about labour reforms is behind the diesel and petrol scarcity and causing long queues at many of the country's 10,250 fuel stations.
It has resulted in blockades across French cities, towns, bridges and motorways.
The dispute comes at one of the busiest times of year as UK motorists head there for the long bank holiday weekend.
The RAC believes that 53% of French stations are now hit.
Simon Williams, fuel spokesman for the RAC, said: "People will have spent a lot of money on holidays so they will naturally be very reluctant to cancel their trips.
"The best advice is to make sure you have a full tank before you cross to France. Ideally, you should have enough fuel to get you comfortably to your destination.
"If you are holidaying in Northern France, depending where you cross, you might well not have to refuel at all or only require a top-up.
"If, however, you are travelling a longer distance in France it's vital you go in search of fuel well before you need it and accept delays and rationing.
"Motorists should also know how far a fuel tank will take them at their vehicle's average fuel economy and drive fuel efficiently at all times by not accelerating too harshly and maintaining a steady speed wherever possible.
"The best website to look at is which has a map indicating showing fuel stations are affected by shortages, either partially or fully.
"It can also help you locate fuel stations.
"The RAC is not advising the use of fuel cans as they are unlikely to make sufficient difference if you are going any considerable distance.
"The limits set by the Government for carrying petrol and diesel in approved containers on a ferry are a maximum quantity five litres per vehicle but some forbid you from carrying petrol altogether."
Copyright Press Association 2016. Motoring News articles do not reflect the RAC's views unless clearly stated.