Last year, Cologne was the subject of worldwide scandal after groups of young men, mostly of African or Middle Eastern heritage, systematically surrounded, groped, raped and robbed women during New Year festivities in the city center.
Cologne's chief of police has rejected criticism over accusations that officers used racial profiling while conducting identification checks on New Year's Eve.
This year, Cologne police were far better prepared. "The clear aim was to prevent similar events to previous year".
In total 650 people were stopped by the 1,500 officers surrounding the city.
Green party co-chair Simone Peter said the tighter security in the city clearly limited violence and attacks during this year's celebrations - but she questioned the legality of police tactics.
Al Jazeera has reached out to Cologne's police department for comment but has yet to receive a response.
Mathies said almost all of the men detained overnight were from North Africa, and that their "characteristics were such that potential crimes could indeed be expected".
However, police reports from 2015 show most of the men arrested or suspected a year ago were from the immigrant community. Hover, despite succeeding in that task, Cologne police had ignored the job of protecting people from discrimination, he added.
Mathies said that German men had also been checked during the night.
As part of an effort to avoid a repeat of the holiday horrors, Cologne police this year detained more than 600 men who hailed from North African countries - or who appeared to.
"I find this term extremely dehumanizing", former politician Christopher Lauer told dpa.
Vice Chancellor Gabriel stood by police chied Mathies, however, saying that "police have done nothing but describe the reality with their profile "Nafris / North Africans".
At issue was the use of the word "Nafris" - according to police, an internal term to describe young men from North Africa "who have been attracting attention for years for their readiness to use violence and/or to commit criminal offences".
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