Britons heading to France for half-term holidays have been warned they face disruption caused by the country's ongoing strikes over pension reform.
The UK Foreign Office has issued advice extending to all modes of transport.
On the Foreign Office website, it warned: "Wildcat strikes continue to cause substantial and unpredictable disruption across the country.
"Those affected are advised to monitor local and UK media reports for more information."
Those who are taking their cars to the continent could face particular difficulties because of fuel shortages caused by blockades of refineries across France.
Some motorways are also being affected by "go slow" protests.
Britain's RAC motoring organisation says it has received a 10% increase in calls from members seeking advice on travelling to France. However it says, so far, it has not seen a rise in the number of people facing difficulties in the country as a result of fuel supply problems.
It echoes the advice of the Foreign Office that drivers should ensure they have sufficient fuel to complete their journey, and to fill up regularly when possible.
For those thinking of taking extra fuel with them when taking their car to the continent by sea, the company P&O Ferries has asked customers to note "that the carriage of extra fuel in jerricans or containers is prohibited on our vessels."
Some hire car companies are suggesting customers might wish to pay up front for fuel to avoid having to refill before returning the car.
Avis is warning holiday-makers planning to drive further afield, who will need to re-fuel during their trip, to be more vigilant of their fuel tank so that they do not get caught short.
A spokeswoman for Avis said: "Although authorities in France are due to be enforcing the opening of fuel depots across the country, travellers should not assume that this will take effect across all stations."
Whilst Eurostar trains are expected to be unaffected by the industrial strife, it is believed onward journeys on connecting trains will be affected.
Eurostar has offered customers connecting within France who will have difficulty getting to or from their Eurostar station, or wish to postpone their journey, the option of exchanging their ticket for free (subject to availability of the fare purchased).
The company's website states that Eurostar tickets can be exchanged up to 60 days after the initial date of travel for a journey in the next 90 days.
More detailed information about problems on internal French railways can be can be found on the SNCF website. The site, which is in French, includes real-time train running information.
Metro trains in Paris are also facing disruption. It is understood that while travel around the capital city is now difficult, there has not been a complete shutdown of public transport.
Flights have not been unaffected either. On Thursday morning protesters managed to blockade Marseille Airport for a short period.
British Airways (BA) says that since the start of the industrial action it has had to make a number of schedule changes. However, it says often it has been able to re-book people for the same day or re-route people to a nearby destination from where they can travel onwards by other means.
A BA spokesperson said: "We have no crystal ball on how things will be in half-term week, but rest assured, we will do everything we can to make alternative arrangements, be that more flights or bigger planes."
The airline is also advising passengers to enter their contact details when booking online. That way if any problems arise company staff will contact them directly to advise them of their options.
A spokesman for budget airline Easyjet said it had been forced to cancel a small number of flights after receiving guidance from Air Traffic Control and said those affected needed to contact its customer services department. On its website it said it was working with the French government to try to minimise impact on travellers.
The UK Foreign Office has warned that cross-channel ferry ports could also be targeted by protesters.
A spokesman for P&O Ferries said so far its services had been largely unaffected, and added its rival operator Sea France had continued sailing too.
It is anticipated that if rail and air transport services are hit, that the ferries might end up soaking up additional custom.
Most ferry companies have websites which are constantly updated with sea conditions and sailing times.
Foreign Office advice
Foreign Office officials say they are closely monitoring the situation but at this stage they have not received large amounts of requests for help from Britons in France.
However for anyone who does find themselves in difficulty there are 12 British consulates across the country, including the main embassy in Paris and other offices in places such as Lille, Marseille, Bordeaux, and Nice.
UK citizens are being advised to stay away from any demonstrations and to consult the Foreign Office website for up-to-date guidance.
The Association of British Insurers (ABI) advises travellers to closely examine their insurance policies to find out exactly how they will be covered if the strike affects them.
A spokesman said: "Check the terms and conditions of your travel contract. Most policies will cover delay and curtailments as a result of strikes, industrial action or adverse weather. In regards to cancellations, travellers will have to check the details of their individual policies."