The California Tort Claims Act is the act that governs filing claims against a government entity. The Tort Claims Act is found in Division 3.6 of the Government Code, Govt. Code ยงยง 810 et seq. Typically, one must first give written notice within 6 months of filing an actual lawsuit, giving the governmental agency time to settle the claim.
References
California Tort Claims Act Wikipedia(Text) CC BY-SA