(a) When otherwise authorized by law to levy occupation taxes on businesses, trades, and professions, a municipality shall be permitted to levy the taxes on businesses, trades, and professions which are licensed by or registered with the state. This Code section shall not be construed to repeal any express limitations on such municipal authority contained in general law.

(b) Nothing contained in this Code section shall be construed to authorize the municipal licensing or taxation of businesses, trades, or occupations operating motor vehicles required to be registered with the Public Service Commission of this state.