An officer or employee shall not accept or receive, directly or indirectly, from any person operating within the territorial limits of a municipality any interurban railway, bus line, street railway, gas works, waterworks, electric light or power plant, heating plant, telegraph line, telephone exchange or other business using or operating under a public franchise, any frank, free pass, free ticket or free service or accept or receive, directly or indirectly, from any person any other service upon terms more favorable than is granted to the public generally, except that the prohibition of free transportation shall not apply to police officers or firefighters in uniform. Free service to the municipal officials provided by any franchise or ordinance shall not be affected by this section.