The declaration is likely to harm relations between Paris and Beijing just two weeks before the Winter Olympics.
ADVERTISEMENTFrance has joined other western countries in formally condemning China's crackdown on Uyghur Muslims as "genocide".
The French Assembly adopted a resolution on Thursday that officially recognises the treatment of the Uyghur minority in China as a crime against humanity.
The declaration comes just two weeks before the start of the 2022 Winter Olympics in Beijing and was almost unanimously approved by French MPs.
NGOs have long accused China of detaining more than one million Uyghurs and other Turk minorities in vast labour camps in the northwestern province of Xinjiang.
Beijing rejects the term "genocide" and has described the camps as vocational training centres to combat extremism.
"The French National Assembly's resolution ... ignores reality and common sense in law," said Chinese foreign ministry spokesperson Zhao Lijian.
"This is a gross interference in China's internal affairs. China is strongly opposed to it," he told a regular news conference on Friday.
But the World Uyghur Congress has welcomed the move in France as "a necessary step towards wider international recognition of the Uyghur genocide".
French MPs have also called on France's government to adopt a similar resolution and take "necessary measures" to protect the minorities.
Minister Delegate for Foreign Trade, Franck Riester, referred to "systematic violence" and "damning testimony" on Thursday but argued that the formal recognition of genocide was a matter for international organisations and not the government.
Riester added that the plight of Uyghur Muslims would be "discussed at the highest level" during talks with Chinese officials.
French President Emmanuel Macron had referred to violence against Uyghur Muslims in his speech to the European Parliament on Wednesday.
A number of other countries -- including Belgium, Canada, the United States, and the United Kingdom -- have previously passed motions referring to a Chinese "genocide" against Uyghurs.
The Netherlands was the first EU country to adopt a non-binding resolution in February 2021.
Meanwhile, the European Parliament has previously condemned China for human rights violations "amounting to crimes against humanity".