Filpac-CGT, the union that represents workers in the paper, book and communication industries, said its members took to the streets on 17 December in protest at the intended job cuts.
Up to 1,000 jobs may be lost, with Stora Enso, International Paper (IP), Cascades and Smurfit-Kappa all announcing job cuts and mill closures in the Nord/Pas-de-Calais area of northern France.
A spokesman for affiliate union ICEM said companies were ignoring their social responsibilities.
"They are in danger of creating a genuine social earthquake."
The closures include two Smurfit-Kappa converting operations and IP's Marasquel mill, which is due to shut at the end of next year.
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