François Hollande demanded on Tuesday that Lakshmi Mittal, the steel magnate, guarantee the long-term future of workers at a disputed plant in northern France or face the threat of a state takeover of the operations.
Stepping up the pressure on the chief executive of ArcelorMittal during an hour-long meeting at the Elysée palace, President Hollande told Mr Mittal the 629 jobs under threat from the proposed closure of two blast furnaces at Florange must be saved.
The talks, described by both sides as business-like, followed an unprecedented public dispute between the two sides sparked by an outspoken attack on the company by Arnaud Montebourg, the industry minister, who accused it of lying and blackmail and suggested it was no longer welcome in France.
In a statement after the talks, the Elysée said: "The president reaffirmed his determination to guarantee permanently the employment at the site and presented different possible options."
Before the meeting, Mr Hollande told reporters he would put on the table the option of the temporary nationalisation of Florange if ArcelorMittal refused French demands to keep the site open.
"Nationalisation is part of the subject under discussion," he said.
Both sides said talks would continue ahead of a deadline set by Mr Mittal for the resolution of the future of the two blast furnaces. Mr Mittal avoided reporters as he left the meeting.
A French official said: "It is up to ArcelorMittal to decide what to do. The ball is in their court."
ArcelorMittal has given the government until December 1 to find a buyer for the two furnaces, but Paris has insisted they are only viable as part of the whole Florange operation, which includes steel rolling and other processes.
The government wants ArcelorMittal, which employs 20,000 people in France, to commit to redeveloping the blast furnaces or to cede the complete Florange operation, which it would take under state ownership until a private buyer was found.
It says it has had two expressions of interest, but has given no names. The Russian steelmaker Severstal declined to comment on speculation that it was a potential buyer.
ArcelorMittal has rejected those demands, arguing that the remainder of the Florange site is critical for the rest of its French operations.
The confrontation has reignited concerns of the perceived hostility of the Hollande government towards business – although Nicolas Sarkozy, the former centre-right president, also clashed with Mr. Mittal over French closures, including Florange.
On Tuesday, Boris Johnson, the mayor of London, mocked the government's stance on a visit to India, where Mr. Mittal was born, saying investors should turn to the UK instead. "'Venez à Londres, mes amis!' [Come to London, my friends!]," he said.
The government's acute sensitivity over the threat to Florange has been fuelled by rising unemployment, which Mr Hollande pledged during the election campaign to reduce.
Latest figures on Tuesday night showed the number of jobless rose by 45,400 to hit 3.1m in October, its highest level for more than 14 years. Ministers have warned that the figures will get worse, although Mr. Hollande has pledged to reverse the trend by the end of next year.