A Shanghai lawyer who had been helping residents protesting about the demolition of their homes has been jailed.
Zheng Enchong was sentenced to three years for passing state secrets to foreigners.
The chorus of discontent among people whose homes are being demolished to make way for new developments in China's cities is growing.
Several people have recently set themselves alight in Beijing and elsewhere to highlight their desperation over the issue.
State media have been putting out a flood of coverage about the problem.
Yet the jailing of Zheng Enchong, a feisty lawyer in his 50s who has helped many disgruntled residents in Shanghai, is clearly meant to show that the authorities here intend to deal toughly with the protests.
Mr Zheng was given a three-year jail term for passing state secrets to foreigners, which in China can mean little more than talking to western media and human rights groups.
The lawyer was detained in June as he was helping residents with a case alleging complicity between city officials and a disgraced property tycoon to cheat them out of proper compensation.
Despite being stripped of his licence to practise two years ago, Mr Zheng had been advising scores of families.
City officials say people are entitled to complain provided they follow the proper procedures.
But in practice, in recent months police have repeatedly rounded up local people who have been attempting to protest about the demolitions.