Wisconsin Statutes Utilities (Ch. 196 to 201) § 196.60. Discrimination prohibited; penalty

(1)(a) No public utility and no agent, as defined in s. 196.66(3)(a), or officer of a public utility, directly or indirectly, may charge, demand, collect or receive from any person more or less compensation for any service rendered or to be rendered by it in or affecting or relating to the production, transmission, delivery or furnishing of heat, light, water, or power or for any service in connection therewith, than that prescribed in the published schedules or tariffs then in force, or established under this chapter, or than it charges, demands, collects or receives from any other person for a like contemporaneous service.

(b) A public utility or an agent that violates par. (a) shall be deemed guilty of unjust discrimination and shall forfeit not less than $100 nor more than $5,000 for each offense. An officer who violates par. (a) shall be fined not less than $50 nor more than $2,500 for each offense.