France has called on China to end "mass arbitrary detentions" in Xinjiang, where around one million ethnic Uighurs and other Muslim minorities are being held in camps that China calls vocational schools.
"We call on China to put an end to mass arbitrary detentions," a foreign ministry spokesperson told reporters.
Foreign Minister Jean-Yves Le Drian has called on China to close the camps and allow the UN High Commissioner for Human Rights to visit Xinjiang as soon as possible to report on the situation.
The extent and nature of the camps was revealed to the world in a huge leak of documents in mid-November by a member of the Chinese political establishment.
China initially denied the network of internment camps existed, but changed its position recently to say they are vocational schools that combat Islamist extremism through education and training.
Mr Le Drian said the government was paying "close attention to all the testimonies and documents reported by the press".
The documents, obtained by the International Consortium of Investigative Journalists (ICIJ) and published by 17 media outlets worldwide on Sunday, show the strict protocols governing life in the camps in Xinjiang.
In one document, local officials are told to monitor inmates at all times - including during toilet breaks - to prevent escape.
Staff are also banned from befriending inmates and engaging in "personal interactions" to prevent "collusion", the document read.
China's foreign ministry remained dismissive following ICIJ's investigation, with spokesman Geng Shuang accusing "some media" of "smearing China's counter-terrorism and anti-extremism efforts in Xinjiang".