Vets have identified a suspected outbreak of foot-and-mouth disease in a herd of 113 cows on a farm in the Loire region of northwest France.
A local Department of Agriculture official said six of the cattle were discovered with symptoms of the highly infectious disease during the afternoon.
They had all been slaughtered and the rest of the herd would also be killed during the night as a precautionary measure.
"We are talking about quite a serious suspicion. The six animals had lesions on their mouths and hooves," said the spokesman. Tests were being carried out and the first results were expected tomorrow.
Foot-and-mouth disease has spread like wildfire in Britain since it emerged there last month, but there have been no confirmed cases so far in continental Europe.