D.C. Code § 47-2014
It shall be unlawful for any vendor to advertise or hold out or state to the public or to any customer directly or indirectly that the reimbursement of tax or any part thereof to be collected by the vendor under this chapter will be assumed or absorbed by the vendor or that it will not be added to the selling price of the property sold or the taxable services rendered, or if added to said price that it, or any part thereof, will be refunded. Any person violating any provision of this section shall upon conviction be fined not more than the amount set forth in [§ 22-3571.01], or imprisoned for not more than 6 months, or both, for each offense.
D.C. Code § 47-2014
Applicability of D.C. Law 19-317: Section 401 of D.C. Law 19-317 provided that the act shall apply only to offenses committed on or after June 11, 2013.
Compensating-use tax, assumption or refund of tax by vendor unlawful, applicability of this section, see § 47-2209. .