It shall be unlawful for any officer, agent, or employee, or any group of them, of the city to organize a labor union, organization or club of city employees, or to be concerned with or a member thereof, whether such labor union, organization or club is affiliated or not with any local, state, national or international body or organization whose charter, bylaws, rules, custom, policy, or practice govern or control, or has for its purpose the governing or controlling of its members in matter of working time, working conditions, or compensation to be asked or demanded of the city. (Code 1941, Art. 19-6; Ord. Nos. 3392; 5364)