The lecturer at a university engineering institute in the southwestern town of Bordeaux was charged on December 16 but released under judicial supervision, the Paris prosecutor's office said.

The charges against him include "providing information to a foreign power" and "colluding with a foreign power", which can be punished by up to 15 and 10 years in jail respectively, it added.

"This civil servant is suspected in particular of having allowed members of a Chinese delegation to enter restricted areas whose sensitivity had been described as highly significant," it said.

The engineering institute where he works has been partially designated as a "restricted area" since 2019.

Such sites are given extra protection to avoid scientific or technical know-how from being intercepted and used to weaken France's "means of defence" or "compromise its security", as well as other potential uses, according to the penal code.

The academic's lawyer did not reply to a request for comment.

An investigation was opened in early 2024 after an alert from the authorities on an incident at the Bordeaux university.

Along with several other people, he was detained for questioning in February last year. After the authorities examined devices seized in the probe, the French academic was called back for more questions.

French publication Intelligence Online described the man as a "recognised expert, nearing the end of his career" who had been cooperating with Chinese colleagues since his student days.

He "has even spent two months per year at Xiamen University since the late 2010s", it said, adding its School of Mathematical Sciences was "among the most prestigious in the country".