Dutch police have arrested dozens of people during a protest over Black Pete, a controversial black-faced sidekick to the local St Nicholas.
The police said most of the 90 people were arrested for protesting in a non-designated area in the city of Gouda.
While surveys show most Dutch people do not want to change the tradition, Black Pete is increasingly viewed as an outdated stereotype.
The Dutch version of the St Nicholas legend depicts him arriving by boat from Spain with armies of Black Petes.
Trouble broke out in Gouda, selected as the city to kick off this year's festivities, during a re-enactment of the arrival of Nicholas and his Black Petes.
State TV showed footage of scuffles as protesters unfurled banners reading "Black Pete is racism".
Police said protesters had been forbidden from demonstrating at the re-enactment, but refused to move away.
The Black Pete character is causing mounting controversy in the Netherlands.
Last year, hundreds of people staged a protest in Amsterdam.
Earlier this year, Amsterdam's regional court said the image of Black Pete "with his thick red lips, being a stupid servant, gives rise to a negative stereotyping of black people".
The court ordered Amsterdam's authorities to review the festival. However, this ruling was overturned by a higher court.
Correction 3 December 2014: This report has been amended to make clear that the Amsterdam court's ruling was later overturned.