The viral strain has killed 91 people since 2003, most of them in Asia.
France confirmed its first case on Saturday after lab tests were carried out on a wild duck found dead in a southeastern village. The same day, India reported its first outbreak among poultry.
India, the world's second most populous nation and a major poultry producer, has begun culling to stop bird flu spreading in birds and people.
A senior official said the suspected case, a 27-year-old poultry farm owner, died on Friday.
Vatsala Vasudev, the district administrator of Surat in western Gujarat state, speaking to Reuters, said: "Local tests have confirmed bird flu, but we have sent samples to the national laboratory. A final report is awaited."
Adding to the sense of crisis in India, blood samples of eight people have been sent for testing.
India's victim of the virus was
said to be a poultry farm owner
Four other people, including three children, were under observation. It was unclear if the farm owner was among the eight being tested.
Vijay Satbir Singh, Maharashtra's leading health official, said: "We sent blood samples of these people who are associated with poultry because they had cold and cough."
Indian health workers and farmers began culling chickens on Sunday.
In France, a dead duck was found on Monday in a bird reserve 30km northeast of Lyon, France's third-largest city, the Agriculture Ministry said.
On Saturday, officials had announced that at least some of the chickens, of the 30,000 that died in Navapur in western Maharashtra over the past week, were infected with the H5N1 strain.
France's food safety agency, AFSSA, "confirmed the presence of a highly pathogenic H5N1 virus on a duck found dead on 13 February in the town of Joyeux," the ministry said in a statement on Saturday night.
Elsewhere in the European Union, H5N1 cases have been reported recently in Austria, Germany, Greece, Italy and Slovenia.
France, the EU's top poultry producer, is already on alert to try to ensure that bird flu does not spread from the wild to its 200,000 farms that raise 900 million birds each year. All fowl have been ordered indoors or vaccinated against a background of fears of an outbreak in France.
The ministry said the strain was 99% identical to the virus that swept from Asia to Europe and Africa and raised fears of a worldwide flu pandemic if it mutates into a form easily transmitted between humans.
Officials said on Friday the duck was found to have been infected with the H5 subtype of avian flu, but only Saturday's lab test confirmed that the virus was the H5N1 strain.
In line with new EU anti-bird flu measures adopted on Friday by the European Commission, French officials set up a three-kilometre protection zone around the spot.
"France has been preparing for this situation for a long time"
Veterinarians were checking poultry in the zone, while the movement of live poultry to and from the area was banned and wild birds were being watched more closely, the ministry said.
The ministry statement said the government had already taken all measures necessary to react to H5N1 contamination in a wild bird as soon as there was a suspect case, and no further measures were needed.
Before the case was confirmed as H5N1, Jacques Chirac, the French president, called for a calm but serious approach to the bird flu case.
"France has been preparing for this situation for a long time," Chirac told reporters during a trip to Thailand. "Our action plans have been constantly adapted."
At a news conference in Paris on Saturday, Dominique Bussereau, the agriculture minister, said that 900,000 birds across France would be vaccinated.
Indonesia confirmed on Saturday that a 19th person had died of bird flu, which has been reported in chickens and other domesticated fowl in most provinces of the sprawling country of 220 million people and 17,000 islands.