(a) Except as provided in subsection (c) of this section, no person retired for service or disability, and in receipt of a retirement allowance under the Retirement System, shall serve in any elective or appointive position in the City and County service, including membership on boards and commissions, nor shall such persons receive any payment for service rendered to the City and County after retirement, provided that service as an election officer or juror, or in the preparation for or the giving of testimony as an expert witness for or on behalf of the City and County of San Francisco before any court or legislative or administrative body, shall not be affected by this section or by Section 8.509, Section 8.546 or Section 8.581 of the Charter.
(b) Should any retired person, except persons retired for service prior to January 8, 1932, and persons retired because of disability incurred in the performance of duty, engage in a gainful occupation prior to attaining the age of 62, the retirement board shall reduce that part of his/her monthly pension or retirement allowance which is provided by contributions of the City and County, to an amount which, when added to the amount earned monthly by him/her in such occupation, shall not exceed the compensation on the basis of which his/her pension or retirement allowance was determined.
(c) Limited employment in positions requiring special skills or knowledge:
(1) A retired person, who is a certificated employee, may enter into a consultancy contract with the San Francisco Unified School District or the San Francisco Community College District to the extent authorized by state law. Notwithstanding any other provisions of this Charter to the contrary, a certificated employee who enters into such a consultancy contract shall not be reinstated as a member of the Retirement System. No deduction shall be made from his or her compensation as contributions to the Retirement System, and his or her retirement allowance shall not be terminated or suspended.
(2) A retired person may be employed in a position other than a certificated position, requiring special skills or knowledge, for not to exceed 120 working days or 960 hours, whichever is greater, in any one fiscal year and may be paid for that employment. That employment shall not operate to reinstate the person as a member of the Retirement System or to terminate or suspend the member's retirement allowance, and no deductions shall be made from his or her salary as contributions to the Retirement System. Furthermore, this employment shall not replace a permanent civil service employee.