The Commission said that it had conducted unannounced investigations at paper envelope manufacturers in France, Denmark, Spain and Sweden.
"The Commission has reasons to believe that the manufacturers concerned may have, amongst others, coordinated price increases and allocated customers on several European markets," said a Commission statement.
The Commission, which enforces EU competition law, said that the fact that the manufacturers were subjected to the unannounced inspections does not mean that they are guilty of any competition law offence.
"Unannounced inspections are a preliminary step in investigations into suspected cartels," said the Commission statement. "The fact that the Commission carries out such inspections does not mean that the companies are guilty of anti-competitive behaviour nor does it prejudge the outcome of the investigation. The Commission respects the rights of defence, in particular the right of companies to be heard in antitrust proceedings."
There is no deadline for the next stage of any action the Commission might take, it said.
