France's ongoing strike movement has severely curtailed the revenues of its state-owned rail company by about 400 million euros (443.1 million dollars), according to the firm's boss.

"That is already a considerable sum," SCNF chairman Jean-Pierre Farandou told the Tuesday edition of Le Monde.

SCNF said that rail travel continued to see disruptions on Christmas Eve, with only two-fifths of high-speed TVG services in operation. Meanwhile, in Paris, several metro lines were closed.

Numerous trade unions have held continuous strikes throughout December in protest against French President Emmanuel Macron's plans to reform and unify the country's pension system.

At the weekend, Macron called for the strikes to be put on hold over the holidays, making an appeal on behalf of the French people. However, his request has not been heeded.

Talks between the government and the unions are set to begin on Jan. 7.