Section 602. No officer or employe shall accept or receive, directly or indirectly, from any person operating within the territorial limits of a city 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 such prohibition of free transportation shall not apply to policemen or firemen in uniform. Nor shall any free service to the city officials heretofore provided by any franchise or ordinance be affected by this section.