Cal. Food & Agr. Code § 5343.5
At any inspection station maintained at or near the California border by the director pursuant to Section 5341, the following sign shall be conspicuously posted in block letters not less than four inches in height:
"NOTICE: IF YOU ARE A CALIFORNIA RESIDENT, THE FEDERAL GUN CONTROL ACT MAY PROHIBIT YOU FROM BRINGING WITH YOU INTO THIS STATE FIREARMS THAT YOU ACQUIRED OUTSIDE OF THIS STATE.
IN ADDITION, IF YOU ARE A NEW CALIFORNIA RESIDENT, STATE LAW REGULATES YOUR BRINGING INTO CALIFORNIA HANDGUNS AND OTHER DESIGNATED FIREARMS AND MANDATES THAT SPECIFIC PROCEDURES BE FOLLOWED.
IF YOU HAVE ANY QUESTIONS ABOUT THE PROCEDURES TO BE FOLLOWED IN BRINGING FIREARMS INTO CALIFORNIA OR TRANSFERRING FIREARMS WITHIN CALIFORNIA, YOU SHOULD CONTACT THE CALIFORNIA DEPARTMENT OF JUSTICE OR A LOCAL CALIFORNIA LAW ENFORCEMENT AGENCY."
Ca. Food and Agric. Code § 5343.5