D.C. Code § 10-1104.02
The Mayor shall, in connection with authorizing the use of any public space under the authority of this subchapter, require the person authorized to use such space, prior to any such use, to secure a policy of public liability and property damage insurance or other acceptable security providing for such minimum limits of liability as may be required by the Mayor. Any such insurance policy shall include the District and its officers and employees as additional parties insured and shall be cancellable only after 30 days written notice of such cancellation has been received by the Mayor. No such use of public space shall be authorized or continued for any period unless such insurance or other security is maintained in full force and effect during that period. Nothing herein contained shall be construed as requiring either the United States or the District to secure a policy of public liability and property damage insurance or other security covering any use of public space by either of the said governments under the authority of this subchapter.
D.C. Code § 10-1104.02