Surveillance video from the incident in February shows the woman being knocked down, then kicked and punched.
The 34-year-old victim was left unconscious.
8 suspects sought after woman brutally assaulted near City Hall
The lawsuit is against Marriott, which owns the W Hotel and the Element Hotel at 15th and Chestnut streets where the assault happened.
The suit claims the hotels were negligent in maintaining safe premises on the sidewalk outside its building.
Marriott is not commenting on the lawsuit.
The lawsuit also names the parents of seven juvenile suspects as defendants.