The 336 staff at the factory who were made redundant in April of this year want Renault SA (RENA.PA) and PSA Peugeot Citroen (PEUP.PA) to pay them 30,000 euros ($41,800) each in return for its remaining stocks of equipment and machinery.

"The bottles of gas have already been placed at various parts of the factory and are connected with each other," CGT trades union official Guy Eyermann told France Info radio.

"If Renault and PSA refuse to give us that money it could blow up before the end of the month," he added