D.C. Code § 34-704
It shall be unlawful for any person to solicit, accept, or receive any rebate, concession, or discrimination in respect to any service in or affecting or relating to any public utility or the production, transmission, delivery, or furnishing of heat, light, water, or power, or any liquid, steam, or air, or the conveying of telegraph or telephone messages within the District of Columbia by a public utility, or for any service in connection therewith whereby any such service shall, by any device whatsoever or otherwise, be rendered free or at a less rate than that named in the schedules and tariffs in force as provided in this subtitle, or whereby any service or advantage is received other than is in this subtitle specified. Any person violating the provisions of this section shall be deemed guilty of a misdemeanor, and on conviction thereof shall be punished by a fine of not less than $200 nor more than $1,000 for each offense.
D.C. Code § 34-704