The French government had this autumn expressed optimism that the plant and its 850 employees would be saved, but Ford said it had told the plant's works council that it had rejected the bid made by transmission supplier Punch Powerglide.

"Despite thorough and rigorous talks over the past nine months, and the best efforts of both sides, the plan put forward by the potential buyer presents significant risks," Ford said in a statement to the works council.

"We do not believe that the prospective buyer's plans offer the level of security or protection, or limit the risk of possible future job losses, that we would like for the employees," added the company.

The likely job losses will be a blow for President Emmanuel Macron, coming at a time of public rebellion over his reforms to liberalise the economy, including an easing of labour laws, and battles to haul down the country's stubbornly high unemployment.

Finance Minister Bruno Le Maire in September had described Punch Powerglide as a "credible, solid buyer."