No person, firm or corporation shall display any sign or use any title or designation such as “Licensed” or “Registered” which would indicate that such person, firm or corporation has been licensed or registered by the City and no person, firm or corporation in the City shall display any sign, or use any title or designation, indicating that such person, firm or corporation is engaged in the business of installing any work which, in the City, may, under the provisions of this Code, be installed only by licensed or registered installers, unless such person, firm or corporation has been licensed or registered under the applicable provisions of this Code, or under applicable provisions of the Codified Ordinances, and such license or certificate of registration has not lapsed or been revoked.