The French CGT union has threatened “fire and blood” after oil giant Total announced the closure of its refinery in Dunkirk.
Workers there have been on strike and in occupation since mid-January against the cuts.
In February the action spread to every Total plant.
Some workers at other oil companies joined the strikes, leading to a crisis for the government on the eve of regional elections set for this weekend.
But with victory possible, union leaders called off the action.
Total made some promises about other refineries, but guaranteed no future for Dunkirk.
Business analysts predict that the company might now try to sell Lindsey, its British refinery on Humberside, to cut capacity as the economy remains stagnant.