Bild said neither police reports of that night nor an investigation following the paper's report could confirm any of the allegations.
The article, which has since been removed from the newspaper's website, quoted a celebrity chef and a 27-year-old waitress from an up-market restaurant on Fressgass St.
UNCONFIRMED REPORTS
The chef told a Bild reporter that a group of about 50 Arab-looking men had rampaged through his restaurant and others nearby during New Years celebrations. He said they sexually assaulted women and stole items including jackets.
The waitress was quoted as saying: "they grabbed me under my skirt, between the legs and on my breast - Their hands were everywhere."
But attempts by competing media to further report on the story met a string of confused restaurant owners and regular customers who insisted they had never seen any kind of 'sex mob'.
Prosecutors have opened an investigation into both witnesses' claims and authorities have searched the apartment of the waitress.
"Masses of refugees were not responsible for any sexual assaults in the Fressgass over New Year. The accusations are completely baseless," police told local media, emphasising they had received no complaints of any disturbance in the area on New Year's Eve.
"Interviews with alleged witnesses, guests and employees led to major doubts with the version of events that had been presented ... One of the alleged victims was not even in Frankfurt at the time the allegations are said to have taken place," police added.
The report came a year after New Year's Eve 2015, when hundreds of women complained to police of being sexually attacked by migrants in the western city of Cologne, sparking a huge backlash against the 890,000 asylum seekers who arrived in Germany that year.
FAKE NEWS PLAGUE
The 'rioting sex mob' is one of a string of recent 'fake news' stories targeting refugees in Germany. Reports of a mob changing 'Allahu akbar' before setting alight Germany's oldest church was quickly shown to be false. Another falsely alleged that a refugee who posed with Chancellor Angela Merkel for a 'selfie' had ties to terrorism.
The centre-right Bild newspaper, founded in 1952 and a circulation measured in millions, has been repeatedly accused of inciting racial tensions against immigrants in recent years. But it has been unequivocal in its apology for this report.
Bild's editor for digital news, Julian Reeichelt, tweeted that there would be consequences for the false report: "We apologise for our own work. I'll shortly announce what Bild will do about it."