Cal. Penal Code § 490.5

(a) Upon a first conviction for petty theft involving merchandise taken from a merchant’s premises or a book or other library materials taken from a library facility, a person shall be punished by a mandatory fine of not less than fifty dollars ($50) and not more than one thousand dollars ($1,000) for each such violation; and may also be punished by imprisonment in the county jail, not exceeding six months, or both such fine and imprisonment.
(b) When an unemancipated minor’s willful conduct would constitute petty theft involving merchandise taken from a merchant’s premises or a book or other library materials taken from a library facility, any merchant or library facility who has been injured by that conduct may bring a civil action against the parent or legal guardian having control and custody of the minor. For the purposes of those actions the misconduct of the unemancipated minor shall be imputed to the parent or legal guardian having control and custody of the minor. The parent or legal guardian having control or custody of an unemancipated minor whose conduct violates this subdivision shall be jointly and severally liable with the minor to a merchant or to a library facility for damages of not less than fifty dollars ($50) nor more than five hundred dollars ($500), plus costs. In addition to the foregoing damages, the parent or legal guardian shall be jointly and severally liable with the minor to the merchant for the retail value of the merchandise if it is not recovered in a merchantable condition, or to a library facility for the fair market value of its book or other library materials. Recovery of these damages may be had in addition to, and is not limited by, any other provision of law which limits the liability of a parent or legal guardian for the tortious conduct of a minor. An action for recovery of damages, pursuant to this subdivision, may be brought in small claims court if the total damages do not exceed the jurisdictional limit of that court, or in any other appropriate court; however, total damages, including the value of the merchandise or book or other library materials, shall not exceed five hundred dollars ($500) for each action brought under this section.
The provisions of this subdivision are in addition to other civil remedies and do not limit merchants or other persons to elect to pursue other civil remedies, except that the provisions of Section 1714.1 of the Civil Code shall not apply herein.
(c) When an adult or emancipated minor has unlawfully taken merchandise from a merchant’s premises, or a book or other library materials from a library facility, the adult or emancipated minor shall be liable to the merchant or library facility for damages of not less than fifty dollars ($50) nor more than five hundred dollars ($500), plus costs. In addition to the foregoing damages, the adult or emancipated minor shall be liable to the merchant for the retail value of the merchandise if it is not recovered in merchantable condition, or to a library facility for the fair market value of its book or other library materials. An action for recovery of damages, pursuant to this subdivision, may be brought in small claims court if the total damages do not exceed the jurisdictional limit of such court, or in any other appropriate court. The provisions of this subdivision are in addition to other civil remedies and do not limit merchants or other persons to elect to pursue other civil remedies.
(d) In lieu of the fines prescribed by subdivision (a), any person may be required to perform public services designated by the court, provided that in no event shall any such person be required to perform less than the number of hours of such public service necessary to satisfy the fine assessed by the court as provided by subdivision (a) at the minimum wage prevailing in the state at the time of sentencing.
(e) All fines collected under this section shall be collected and distributed in accordance with Sections 1463 and 1463.1 of the Penal Code; provided, however, that a county may, by a majority vote of the members of its board of supervisors, allocate any amount up to, but not exceeding 50 percent of such fines to the county superintendent of schools for allocation to local school districts. The fines allocated shall be administered by the county superintendent of schools to finance public school programs, which provide counseling or other educational services designed to discourage shoplifting, theft, and burglary. Subject to rules and regulations as may be adopted by the Superintendent of Public Instruction, each county superintendent of schools shall allocate such funds to school districts within the county which submit project applications designed to further the educational purposes of this section. The costs of administration of this section by each county superintendent of schools shall be paid from the funds allocated to the county superintendent of schools.
(f)
1. (1) A merchant may detain a person for a reasonable time for the purpose of conducting an investigation in a reasonable manner whenever the merchant has probable cause to believe the person to be detained is attempting to unlawfully take or has unlawfully taken merchandise from the merchant’s premises.
  A theater owner may detain a person for a reasonable time for the purpose of conducting an investigation in a reasonable manner whenever the theater owner has probable cause to believe the person to be detained is attempting to operate a video recording device within the premises of a motion picture theater without the authority of the owner of the theater.
  A person employed by a library facility may detain a person for a reasonable time for the purpose of conducting an investigation in a reasonable manner whenever the person employed by a library facility has probable cause to believe the person to be detained is attempting to unlawfully remove or has unlawfully removed books or library materials from the premises of the library facility.
2. (2) In making the detention a merchant, theater owner, or a person employed by a library facility may use a reasonable amount of nondeadly force necessary to protect himself or herself and to prevent escape of the person detained or the loss of tangible or intangible property.
3. (3) During the period of detention any items which a merchant or theater owner, or any items which a person employed by a library facility has probable cause to believe are unlawfully taken from the premises of the merchant or library facility, or recorded on theater premises, and which are in plain view may be examined by the merchant, theater owner, or person employed by a library facility for the purposes of ascertaining the ownership thereof.
4. (4) A merchant, theater owner, a person employed by a library facility, or an agent thereof, having probable cause to believe the person detained was attempting to unlawfully take or has taken any item from the premises, or was attempting to operate a video recording device within the premises of a motion picture theater without the authority of the owner of the theater, may request the person detained to voluntarily surrender the item or recording. Should the person detained refuse to surrender the recording or item of which there is probable cause to believe has been recorded on or unlawfully taken from the premises, or attempted to be recorded or unlawfully taken from the premises, a limited and reasonable search may be conducted by those authorized to make the detention in order to recover the item. Only packages, shopping bags, handbags or other property in the immediate possession of the person detained, but not including any clothing worn by the person, may be searched pursuant to this subdivision. Upon surrender or discovery of the item, the person detained may also be requested, but may not be required, to provide adequate proof of his or her true identity.
5. (5) If any person admitted to a theater in which a motion picture is to be or is being exhibited, refuses or fails to give or surrender possession or to cease operation of any video recording device that the person has brought into or attempts to bring into that theater, then a theater owner shall have the right to refuse admission to that person or request that the person leave the premises and shall thereupon offer to refund and, unless that offer is refused, refund to that person the price paid by that person for admission to that theater. If the person thereafter refuses to leave the theater or cease operation of the video recording device, then the person shall be deemed to be intentionally interfering with and obstructing those attempting to carry on a lawful business within the meaning of Section 602.1.
6. (6) A peace officer who accepts custody of a person arrested for an offense contained in this section may, subsequent to the arrest, search the person arrested and his or her immediate possessions for any item or items alleged to have been taken.
7. (7) In any civil action brought by any person resulting from a detention or arrest by a merchant, it shall be a defense to such action that the merchant detaining or arresting such person had probable cause to believe that the person had stolen or attempted to steal merchandise and that the merchant acted reasonably under all the circumstances.
  In any civil action brought by any person resulting from a detention or arrest by a theater owner or person employed by a library facility, it shall be a defense to that action that the theater owner or person employed by a library facility detaining or arresting that person had probable cause to believe that the person was attempting to operate a video recording device within the premises of a motion picture theater without the authority of the owner of the theater or had stolen or attempted to steal books or library materials and that the person employed by a library facility acted reasonably under all the circumstances.
(g) As used in this section:
1. (1) “Merchandise” means any personal property, capable of manual delivery, displayed, held or offered for retail sale by a merchant.
2. (2) “Merchant” means an owner or operator, and the agent, consignee, employee, lessee, or officer of an owner or operator, of any premises used for the retail purchase or sale of any personal property capable of manual delivery.
3. (3) “Theater owner” means an owner or operator, and the agent, employee, consignee, lessee, or officer of an owner or operator, of any premises used for the exhibition or performance of motion pictures to the general public.
4. (4) The terms “book or other library materials” include any book, plate, picture, photograph, engraving, painting, drawing, map, newspaper, magazine, pamphlet, broadside, manuscript, document, letter, public record, microform, sound recording, audiovisual material in any format, magnetic or other tape, electronic data-processing record, artifact, or other documentary, written or printed material regardless of physical form or characteristics, or any part thereof, belonging to, on loan to, or otherwise in the custody of a library facility.
5. (5) The term “library facility” includes any public library; any library of an educational, historical or eleemosynary institution, organization or society; any museum; any repository of public records.
(h) Any library facility shall post at its entrance and exit a conspicuous sign to read as follows:
“IN ORDER TO PREVENT THE THEFT OF BOOKS AND LIBRARY MATERIALS, STATE LAW AUTHORIZES THE DETENTION FOR A REASONABLE PERIOD OF ANY PERSON USING THESE FACILITIES SUSPECTED OF COMMITTING “LIBRARY THEFT” (PENAL CODE SECTION 490.5).”