One patient is a 48-year-old man in the southwestern city of Bordeaux, Health Minister Agns Buzyn told reporters.
Buzyn said the man traveled to China and visited Wuhan before returning to France on January 22. A day later, he sought medical examination and has remained in isolation since then.
"He's in isolation and he's doing well," Buzyn said.
Two other patients have been admitted to a hospital in Paris, the ministry said in a statement.
"It might be because we set up the tests in a very short time making us capable to identify them," the minister told reporters. "What matters is to contain the fire as fast as possible, that's why we need to know the patient's history, find the people that patient was in contact with, to meet them, speak to them and give them the instructions to first of all stay at home and avoid any contact."
The virus, which was first discovered in the city of Wuhan in December, has spread to every province in China, except the remote autonomous regions of Qinghai and Tibet, with the number of infections rising to more than 1,000 worldwide.
As of Friday, the virus had claimed the lives of at least 41 people in mainland China.
Cases of the virus have been confirmed in Hong Kong, Macau, Taiwan, Singapore, South Korea, Thailand, Japan and Vietnam.
CNN's Nicole Chavez wrote from Atlanta, Saskya Vandoorne and Fanny Bobille reported from Paris.