The rap music producer, whose real name is Marion Knight, was arrested in Las Vegas.
The two are accused of chasing a photographer down an alley after they exited a studio. The two then allegedly grabbed her camera, "forcibly," Beverly Hills police Sgt. Max Subin told the Los Angeles Times.
The woman allegedly sustained minor injuries.
Should he be convicted, Knight faces up to 30 years in prison because he has a previous conviction for assault with a deadly weapon. Williams faces up to seven years in prison.
The Los Angeles County District Attorney's office said it plans to set Knight's bail at $1 million and Williams' at $75,000.