Police in riot gear reinforced by security personnel from around the country made 10 arrests because of scattered fights and misbehavior. About 2,000 people joined the anti-facist march while demonstrations by two far-right groups also gathered up to 2,000 people, the police said.
Anti-immigrant sentiment has been on the rise in the Nordic European Union member country of 5.5 million. About 32,500 migrants and refugees arrived during Europe's migrant crisis in 2015. The number came down to 5,600 last year.
'No Nazis in Helsinki!' shouted anti-fascist demonstrators.
Far-right marchers promoted the slogan 'Toward freedom,' and many carried torches. Last week, a court banned a neo-Nazi group called Nordic Resistance Movement, but it took part in a march as the decision has yet to be implemented.
Finland was part of the Russian empire and won independence during the 1917 Russian Revolution, then nearly lost it fighting the Soviet Union in World War II.