No person retired as a member under Section 8.544 after June 30, 1945, for service or disability and entitled to receive 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 person receive any payment for service rendered to the City and County after retirement, provided that service as an election officer or juror shall not be affected by this section.