California Code, Business and Professions Code - BPC § 22949.67

(a) Authorize the initiation of a cause of action under this chapter against a person purchasing, obtaining, or attempting to purchase or obtain an assault weapon, .50 BMG rifle, unserialized firearm, or firearm precursor part from a person acting in violation of this chapter.

(b) Wholly or partly repeal, either expressly or by implication, any other statute that regulates or prohibits any conduct relating to firearms or firearm precursor parts, including, but not limited to, Chapters 1.5 and 2 (commencing with Sections 30400 and 30500, respectively) of Division 10 of Title 4 of Part 6 and Chapter 3 (commencing with Section 29180) of Division 7 of Title 4 of Part 6 of the Penal Code.

(c) Restrict a political subdivision from regulating or prohibiting conduct relating to assault weapons, .50 BMG rifles, unserialized firearms, or firearm precursor parts in a manner that is at least as stringent as the laws of this state.