France will begin vaccinating domestic poultry after the H5N1 bird flu virus killed 15 wild swans in the country's south-east.
News of the death of the swans, found around the numerous ponds that dot the area, underscored the potential for the lethal virus to spread.
On Saturday, authorities confirmed that a nearby turkey farm of more than 11,000 birds had been contaminated, triggering fears of a collapse of the poultry industry in France - the first outbreak of the virus in commercial poultry in the European Union.
Some 400 birds at the farm had died and the rest were slaughtered.
France, the EU's largest poultry producer, is now working to control damage to poultry farmers. President Jacques Chirac, visiting Paris' annual agriculture fair, urged consumers not to panic and to keep eating chicken.
However, Japan - followed by Hong Kong - temporarily banned the import of poultry products from France, including the delicacy foie gras.
The French poultry sector generated more than £2 billion in revenues in 2004, or more than 20 per cent of total EU production.
Elsewhere, a laboratory in Georgia has confirmed the virus has contaminated wild swans there, according to the country's Agriculture Ministry.
The lethal H5N1 bird flu strain has spread from Asia to at least 10 European countries and Africa, and scientists fear it could mutate into a form that is easily transmitted between humans, sparking a pandemic. The disease has killed more than 90 people, mostly in south-east Asia, according to the World Health Organization.