Anthrax has been detected in 23 locations, local authorities said in a statement, with 54 animals killed, mainly bovines.
Vaccination doses for 5,000 cows and 10,000 sheep have been rushed to the area to tackle the worst anthrax outbreak in France in nearly 20 years.
More than 50 cows, sheep and horses have died in France's most serious outbreak of anthrax in two decades, according to officials who have warned of a vaccine shortage.
Authorities in the mountainous Hautes-Alpes region of southeastern France said the infection, which can spread to humans and is deadly in its rarest forms, had spread to 28 farms since June.
Anthrax is transmitted by spores that can stay inactive in the ground for decades, including in the bodies of dead animals.
French vets have been battling to contain the outbreak because the Spanish laboratory which produces the vaccines has been closed throughout August for the summer vacation.
“The state is in talks with its European partners to discuss the availability and purchase of vaccines” which other countries may have stockpiled, said senior regional official Agnes Chavanon Sunday.
Anthrax is an infection spread by spores of the Bacillus anthracis bacteria which occur naturally and can be ingested by livestock and passed on to humans, usually through skin contact, causing black lesions. If left untreated it can be fatal.
Cases of anthrax being passed on to humans are “extremely rare”, said Christine Ortmans, a doctor with regional health agency ARS.
No one has been reported ill during the current outbreak, she stressed.
Cutaneous anthrax — which appears on the skin and is by far the most common form of the infection — is rarely deadly when treated with antibiotics.
But the bacteria which causes it, bacillus anthracis, produces a powerful toxin and has been used as a biological weapon.
Most notoriously a series of attacks using anthrax, delivered through the mail, terrorised the United States in 2001 a week after the carnage of September 11.