About 100 parents rallied outside the Beijing government offices on Friday after their children were denied admission to their primary school of choice, the second such protest in the Chinese capital this month.
At least 30 police, many with video cameras, filmed the parents as they chanted slogans about allowing their children to go to their local school.
A parent who became the ad hoc leader of the gathering was briefly detained by police, said more than 10 parents who saw him being dragged away. The man was released after the parents agreed to disperse.
Earlier this month, about 100 protesters clashed with police after authorities reassigned their children to a school in a rough neighbourhood.
The protests come at a time when educational resources in Beijing have become increasingly stretched while home prices have soared.
"If they had given us prior notice, we would have had time to find another school, but now all registration is closed," said a parent who gave her last name as Yu.
"We don't have any other options but to do as the government says."
The Beijing municipal government has yet to respond to a faxed request for comment.
The primary school that their children were supposed to attend is in Huilongguan in Changping district, a densely populated part of northern Beijing.
The local education board said it wanted the incoming first graders to attend a nearby middle school instead.
People from all over China have moved to Beijing for better job opportunities, schooling and healthcare, but the city's infrastructure has not been able to keep up with demand.
Some schools in better districts have vacancies, as properties in those areas are too expensive for young parents, while schools in places like Huilongguan are at overcapacity.
"The girls have to line up to use the toilets because there are too many children and not enough toilets, so they try not to drink water during the day," said a parent who gave her last name as Wang.
"The local government only cares about building apartments and shopping malls because that way they can raise revenue. They haven't built nearly enough schools for all the residents in the area."