When it comes to the entertainment industry, which is heavily censored in China, the government is particularly sensitive to the influence its stars’ behavior can have — for better or worse — on public opinion.

Shortly after the inquiry began in June, the government announced that it would impose new limits on the salaries of actors, even in privately financed films. No one actor can now earn more than 70 percent of what the entire cast makes or more than 40 percent of production costs of a movie. The statement said the industry was “distorting social values” and “fostering money worship tendencies” with outsize compensation.

The State Tax Administration warned in the statement that others in the entertainment industry could also face investigations unless they stepped forward to declare untaxed income. It set a deadline of Dec. 31, promising that those who complied voluntarily would not have to pay penalties.

For Ms. Fan, the reputational damage has already been done. She was, until this summer, one of the most recognizable women in China, having appeared in dozens of movies and television series and achieved global recognition with roles in the “X-Men” and “Iron Man” franchises.

During what had become an annual star-turn at the Cannes Film Festival in May, she joined Jessica Chastain, Lupita Nyong’o, Marion Cotillard and Penélope Cruz in promoting their roles as superspies in a planned thriller, “355.”

The fate of that role, as well as numerous branding contracts that were abruptly canceled or suspended since then, remains to be seen. Her current whereabouts is not known, though there have been unsubstantiated reports that she has been detained during the course of the investigation.

Ms. Fan’s abrupt fall from public grace has been one of the biggest news sensations in China in recent months, worrying fans and colleagues while delighting others who relished the travails of a rich celebrity.