PSA Peugeot Citroen unions voted on Monday to back plans to cut thousands of jobs and close a plant, the central plank of the French carmaker's efforts to halt ongoing losses.

A majority of unions had agreed last month to back the plan, including 8,000 French job cuts and the closure of Peugeot's Aulnay plant near Paris. But the cuts were delayed by a legal challenge filed by the leftwing CGT and Sud labor groupings.

The Paris high court rejected the dissident unions' latest challenge on Friday, clearing the way for the cutbacks to take effect.

Union officials approved the key restructuring measures by 18 votes to two, an official from the CFTC union said after a works council meeting on Monday.

Peugeot has been running losses of as much as 200 million euros ($260 million) a month and only plans to return to profit in 2015.

Unveiling a further 6.5 percent decline in first-quarter revenues last week, Peugeot said it planned to seek further savings by negotiating labor concessions in such areas as working time and wage restraint.