SHANGHAI — When the Chinese government announced new curbs on property prices this month, homeowners bombarded social networking sites with complaints. They formed long lines at property bureaus to register to sell their homes before the restrictions went into effect.

And some couples went even further: they filed for divorce.

Divorce filings shot up here and in other big cities across China this past week after rumors spread that one way to avoid the new 20 percent tax on profits from housing sales was to separate from a spouse, at least on paper.

The surge in divorce filings is the latest indication of how volatile an issue real estate has become in China in the past decade and how resistant people are to additional taxes.

Worried that housing prices are spiraling out of control and threatening social stability, the central government regularly rolls out measures aimed at damping demand and weeding out speculators.