Hundreds of petrol stations have been closed in France as a result of industrial action by oil workers in a dispute over changes to France's employment laws.

Petrol stations are reportedly running dry, tankers off the southern coast are not being allowed to dock, the government is dipping into precious reserves, and nuclear power capacity has been cut because workers have walked out.

There are also reports of train lines being obstructed.

What exactly is happening?

A union called the CGT is organising a widespread strike which is affecting transport across much of France.

As well as a blockade of six of France's eight oil depots - which earlier this week caused more than 1,600 service stations to be closed - the strike is impacting train and airport services.

15% of flights have been cancelled at Orly Airport in Paris, and several local train and metro services have been affected in the capital.

 Image: Franck Pennant / AP/Press Association Images

How long has it been going on for?

The dispute started earlier this year after the government announced it wanted to make changes to the Code de Travail - a 3,000-page book that sets out all of France's employment rules.

It began with a petition against the proposals that gathered one million signatures, and in mid-March hundreds of people began staging nightly protest rallies, many of which have spiralled into violence.

National days of protest followed with today marking the eighth day of demonstrations.

What changes are being proposed?

The so-called El Khomri Bill - named after France's employment minister Mariam El Khomri - aims to liberalise the labour market in France by making it moderately easier for firms that run into difficulties to lay off workers.

It would also make it possible for some employees to work longer than the 35-hour week set down in current legislation.

The government hopes that freeing the market from some of its restrictions would encourage French companies to hire more people, and help overcome the nation's 10% unemployment rate.

What do the protesters want?

They want French President Francois Hollande's government to scrap the changes to the laws.

The union is fighting to change Article 2 in particular. It sets out how working hours can be agreed at a company level, instead of at sectoral level as has been the case until the new bill comes into force.

What does the government want?

The Prime Minister Manuel Valls is determined not to back down.

He pushed through the new bill on May 10th without a vote in parliament, by employing a rarely-used clause in France's constitution which allows reform by decree.

Valls has maintained his opposition to watering down Article 2, despite some of Hollande's other ministers saying they are prepared to compromise.

What is the fight between Francois Hollande and Manuel Valls about?

Valls was brought in by Hollande to replace his previous left-wing PM Jean-Marc Ayrault, who led the government to heavy losses in local elections.

He hoped that a more "right wing" government would help him achieve progress he promised in tackling France's economic woes.

Valls' tough-talking stance on the economy and immigration has won him admirers on the right but infuriated those on the left.

It is many of those left-wingers who put Mr Hollande in power, by ensuring he was nominated for president.

French President Francois Hollande and French Prime Minister Manuel Valls | Image: Michel Euler / Press Association Images

What does it mean for Mr Hollande's future?

Hollande once said his presidency should be judged on whether he "turned the unemployment curve around".

He has so far failed to do so and, with the changes to labour laws under threat, looks unlikely to do it before next year's presidential elections.

But, with his battle over the changes to the Code de Travail just the latest in a series of difficulties, his popularity has plummeted to as low as 13%.

The fact that his government earlier this month only narrowly won a vote of no confidence in parliament has not helped his cause.

Who is going to win in the dispute?

According to the latest survey in French newspaper Le Point, 62% of French people back the strikers, but this is down from three-quarters who opposed the laws earlier this month.

Valls says that, with rationing at the pumps and a determined stance from the government, it can guarantee fuel supplies for three months.

But if the situation gets more aggressive, it will only take a few more MPs to vote against the government before a new no-confidence vote could wreck Hollande's chances of re-election for good.