It occurred on Sunday, September 4 around 6:30 p.m. during the concert on the 2600 block of the Benjamin Franklin Parkway.
Police say a 19-year-old woman says a man grabbed her right arm and then bit her on the forearm causing broken skin and bruising.
The woman says she did not know the man.
She went to the concert medical tent where she was treated for her injuries.
A nearby concertgoer took pictures of the suspect with a cell phone camera.
He is described as black male, early to mid-30s, with long braided black hair. He was wearing a pink button down shirt, black/white/gray "True Religion" cap, and appears to have a crown tattoo on his chest.
Anyone with information should call 215-686-TIPS (8477) or text a tip to PPD TIP or 773847.