Police said the suspected attackers, including migrants, grabbed their victim’s crotches. Ten people have been arrested in connection with the sexual assaults.
Officers said three Syrians, three Iraqis, two Afghans, one Eritrean and one German were arrested in connection with the sexual assaults in Große Freiheit and Beatles Square.
Firefighters and police were called out to more than 2,000 incidents during the celebrations.
In Hamburg, 14 women were the victims of sex attacks, as more than 45,000 people celebrated New Year’s Eve in the city
A number of troublemakers were spoken to by police and banned from certain areas of the city.
Elsewhere in Germany, police in Augsburg launched investigations into several sex attacks as chaos ripped through the Bavarian town on New Year’s Eve.
Around 150 people celebrated the New Year in Augsburger Königsplatz with police reports of migrants firing rockets into the crowd.
Three young men from Iraq and Syria were banned from the square after firing rockets at several people, police said.
Police launched an investigation after a rocket hit a woman, 30, on the head and a police officer was injured when a firework hit his patrol car.
Eyewitnesses accused three Syrians of being behind the incident, police said investigations are ongoing.
Afghan nationals, aged 19, 21 and 37 were accused of repeatedly groping two 18-year-old girls.
Police said a 31-year-old Iraqi exposed himself to one woman in Ludwigstrasse at around 4am, witnesses have been asked to contact officers.
The mayhem continued into the early hours of New Year’s Day with a knife fight between a Syrian and Iraqi in Ulmerstrasse.
Officers said the Syrian wan was stabbed in the thigh south a pocket knife.
Vandals also set fire to seven cars and used tyres causing €50,000 worth of damage.
In Dortmund five police officers were injured in the chaos which saw police arrest dozens of men.
Officers set up no-go zones near the station and town’s main square with reports of drunk men aggressively approaching police.
Photos and video from the mayhem show smoke flares being thrown into the crowd as troublemakers ignored police warnings from the square’s town speakers.
Police said suspects threw pyrotechnics with bare hands at officers and families with young children.
Riot police armed with shields and helmets watched on as gangs shout “Allahu Akbar” as Syrians celebrate Turkey and Russia brokering a ceasefire for Syria.
A homeless man was rushed to hospital with first degree burns after an unknown person threw a rocket at him.
Rockets also set fire to the roof of the Reinoldi Church.
Police said they are unsure if the blaze was caused by the official fireworks display or people throwing them in the crowd.
Police in Cologne said on Sunday they had prevented a repeat of the assaults and robberies suffered by hundreds of women in Cologne a year ago by screening 650 mostly North African men on New Year’s Eve.
Police detained and screened many of the men at the main railway station as they headed towards the centre of Cologne in western Germany, where the attacks a year earlier fuelled criticism of Chancellor Angela Merkel’s open-door migrant policy.