Health authorities in southwestern France have temporarily banned the sales of oysters from the famous Bay of Arcachon after several people suffered food poisoning, reports Radio France Internationale.
Several cases of acute gastroenteritis have been reported in recent days, so far none of them life-threatening.
Initial investigations on locally farmed oysters confirmed the presence of norovirus, the most common cause of gastroenteritis.
Regional health authorities on Wednesday said fishing, harvesting and sales of all shellfish from Arcachon, a scenic bay on the Atlantic famed for its seafood, should stop temporarily.
"Batches of shellfish harvested or fished in these areas must be withdrawn from sale," said the Gironde prefecture in a statement.
"Anyone in possession of shellfish from these areas is asked not to eat them and to return them to the point of sale."
The ban will hit oyster farmers who plan for increased business at the end of the year, with the delicacy a traditional feature of gatherings on 31 December and 1 January.