The demonstration, in the huge Cite Soleil shantytown, one of the most dangerous districts of the capital, was peaceful.
Dozens of demonstrators, some shouting "Down with the UN," threw stones, broke UN vehicles' windshields, and burned a US flag near Haiti's presidential palace.
The UN has a base there but does not control the neighbourhood, which is run by armed gangs.
The protest follows a violent student demonstration Tuesday against the UN forces.
Since mid-2004 the UN has maintained more than 7,000 troops and 1,200 police in Haiti to help stabilize the poorest country in the Americas.