California Code, Penal Code - PEN § 26020

(a) Upon approval of the sheriff of the county in which the retiree resides, Section 25850 does not apply to any honorably retired federal officer or agent of any federal law enforcement agency, including, but not limited to, the Federal Bureau of Investigation, the United States Secret Service, the United States Customs Service, the federal Bureau of Alcohol, Tobacco, Firearms and Explosives, the Federal Bureau of Narcotics, the United States Drug Enforcement Administration, the United States Border Patrol, and any officer or agent of the Internal Revenue Service who was authorized to carry weapons while on duty, who was assigned to duty within the state for a period of not less than one year, or who retired from active service in the state.

(b) A retired federal officer or agent shall provide the sheriff with certification from the agency from which the officer or agent retired certifying that person's service in the state, stating the nature of that person's retirement, and indicating the agency's concurrence that the retired federal officer or agent should be accorded the privilege of carrying a loaded firearm.

(c) Upon approval, the sheriff shall issue a permit to the retired federal officer or agent indicating that the retiree may carry a loaded firearm in accordance with this section. The permit shall be valid for a period not exceeding five years, shall be carried by the retiree while carrying a loaded firearm, and may be revoked for good cause.

(d) The sheriff of the county in which the retired federal officer or agent resides may require recertification prior to a permit renewal, and may suspend the privilege for cause. The sheriff may charge a fee necessary to cover any reasonable expenses incurred by the county.