PARIS (AFP) - Protesters took to the streets across France on Thursday (Sept 15) for fresh demonstrations against the Socialist government's labour reforms, although opposition to the measures appeared to be running out of steam.

Demonstrators also marched through the eastern city of Belfort where the government is locked in a battle with train-building giant Alstom over the future of an under-threat locomotive factory.

After months of sometimes violent opposition, the measures designed to make France's labour market more flexible were adopted by Parliament in July after being watered down.

But such was the opposition on the left, including from within the Socialist Party's own ranks, the government had to force through the reforms without a vote.

Opponents believe the measures are weighted in favour of employers.

Many of the demonstrations have been scarred by clashes between protesters and riot police, reaching a peak on June 14, just four days after the start of the Euro 2016 football championships in France, when around 40 people were hurt and dozens arrested.

After several months' respite over the summer, unions called for fresh strikes on Thursday, but their impact on flights and trains looked set to be minimal.

Aviation authorities had advised airlines serving Paris airports to cancel 15 percent of their flights Thursday that includes CDG Irish no-frills airline Ryanair announced that it had cancelled dozens of flights to or through France over the strike.

In Belfort, the government is battling to save the historic factory that assembled France's first high-speed TGV train.

Train-maker Alstom had announced it would close the plant to a lack of orders.

The prospect of up to 400 job losses is a headache for the government ahead of parliamentary and presidential elections.

Turnout for the separate labour law demonstrations, which are also expected to take place in the cities of Lyon and Marseille, will be closely watched.

From hundreds of thousands of protesters in the early days of the demonstrations, the numbers dwindled to just 35,000 for the last protests on July 5.

Mr Philippe Martinez, leader of the hardline CGT union driving the demonstrations, has called for workers to keep up the struggle at the company level, "fighting tooth and nail to stop it (the law) crossing the threshold".

French President Francois Hollande, who has yet to announce whether he will seek re-election next April, had hoped for a signature reform to boost his dire approval ratings.