But to some Germans already uneasy about the 1 million asylum seekers their state took in past year the event appeared to support simmering anxieties.
One of the victims claimed that she was raped in the center of the city.
Cologne police have reviewed about 90 criminal complaints from women who described being robbed, sexually harassed and in one case raped as revelers poured into Germany's fourth-largest city from the train station at the foot of its cathedral, police spokeswoman Stefanie Becker said by phone Tuesday.
German police allege dozens of women were assaulted in coordinated sexual attacks in Cologne on Thursday evening.
"The actions of the perpetrators were completely intolerable, and so we expect them to be prosecuted in the toughest possible way", Reker said.
And at a news conference on Tuesday, Heiko Maas, Germany's justice minister, said the ethnic background of the alleged perpetrators was irrelevant.
Anne, 27, told the newspaper she had been groped when she came to the square, which "was full of nearly exclusively men with just a few fearful women among them being stared at".
The police chief said "the assailants' behavior is a real concern for me, also because of the carnival".
Police said they still lack information in the ongoing investigation.
Given that Germany's famous Carnival celebrations are upcoming, the police will surely be on the lookout for more attacks during those events in February. The crowd of around 1,000 men attacked people in the city center in what Albers described as a "crime of a whole new dimension". While the scale of the attacks has left the country shocked at what had transpired, Mayor Henriette has encouraged the people to not jump at conclusions about the attackers; especially with the ongoing debate against the volume of refugees and migrants who fled from Syria a year ago.
A surveillance camera hangs from the roof of the main railway station in Cologne, Germany, January 5.
"It is important to prevent such incidents from ever happening again", said Mayor Reker, as reported in German by RP Online.
The government has said a crowd of up to a thousand people may have been directly or indirectly involved in the incidents.
Cologne Mayor Henriette Reker and President of the Cologne Police Wolfgang Albers (right) arrive for a news conference in Cologne, Germany, today. According to the Times, no arrests were made.