The shipping giant initially reported 70 containers had slipped into the sea off Brittany when the storm lashed the west of the country, causing giant waves offshore but on Wednesday it said that, in fact, the figure was 517.
Environment campaigners Robin des Bois on Friday announced that it was making a legal complaint against the company in the Brittany port of Brest, accusing it of "endangering lives" and pollution and "abandoning waste".
Containers are "a permanent danger for fishermen, coastal communities and the environment", the group said, accusing Maersk and the crew of the boat, Svendborg Maersk, of "unacceptable light-mindedness".
The company says that 85 per cent of the containers were empty.
Coastguards have sent helicopters at hte company's expense to try to find the lost objects but had only recovered 13 by Friday.
The storms that hit France in January will cost insurance companies 150-200 million euros, the boss of the Axa insurance company, Nicolas Moreau, said on Friday.
The bill for damage by Storm Dirk in December was 175-210 million euros.