Chinese officials under investigation often disappear for weeks or even months before the government says anything about their fate. If Mr. Meng has been detained, his case may signal that the tactic is continuing.

In 2013, Li Dongsheng, another vice minister of public security, was investigated for corruption and he was later sentenced to 15 years in prison for taking bribes. Last month, China’s anticorruption agency announced that it was investigating Nur Bekri, one of the few senior Chinese officials from the Uighur ethnic minority. He is a former governor of Xinjiang region in northwest China and most recently was director of the National Energy Administration.

Andrew Wedeman, a political scientist at Georgia State University who studies corruption in China, said Mr. Xi’s anticorruption drive appeared to have cooled from a peak in 2015 but nonetheless was still taking down “tigers” — the Chinese phrase for fallen senior officials.

“By my count, this year they have taken down 17 ‘tigers’ thus far — Meng would be tiger No. 18,” Professor Wedeman said by email. “My sense is that the active phase of the crackdown is now over and we are back to more routine levels. The tiger hunt is, however, definitely still ongoing.”

In France, investigators learned of Mr. Meng’s disappearance when his wife went to the police in Lyon on Thursday evening and explained that she not heard from her husband since his arrival in China, according to an official close to the investigation, who insisted on anonymity and was not authorized to comment publicly.

Mr. Meng’s wife also told the police that she had received threats by telephone and on social media, and the French authorities have provided her with police protection, Agence France-Presse reported.

In a statement, Interpol, the main organization for global police cooperation, said that it was “aware of media reports in connection with the alleged disappearance” of Mr. Meng. “This is a matter for the relevant authorities in both France and China,” the statement said.