The R&B star, 32, is alleged to have struck the woman on Friday 18 June.
Officers were called to an area in the San Fernando Valley, southern California, at 7.30am local time, a spokesman for the Los Angeles Police Department said.
A crime report for battery has been completed and LA city’s attorney’s office will now consider whether to bring any charge.
The US singer wasn’t present when police arrived at the scene, the spokesman said.
“The victim advised that she and the suspect argued and the suspect struck her,” he added.
Chris Brown’s representatives have not yet responded to Newsbeat’s request for comment.
The Grammy-winning artist received five years probation and a community service order for assaulting his then-girlfriend, Rihanna, in 2009.
In 2017, another former girlfriend – actress and model Karrueche Tran – was granted a five-year restraining order against him.