D.C. Code § 6-402
Upon the filing of such plat and petition in the Office of the Mayor of the District of Columbia or when the Mayor shall deem that the public interests require it, the said Mayor shall institute condemnation proceedings in the Superior Court of the District of Columbia, by a petition in rem, particularly describing the land to be taken, which petition shall be accompanied by duplicate plats, to be prepared by the Surveyor of said District, showing the location of said proposed building lines, the number of square feet to be taken from each lot or part of lot and the boundaries thereof in each square or block, and such other information as may be necessary for the purposes of such condemnation. Upon the filing of such petition, 1 copy of the plat, indorsed with the docket number of the case, shall be returned by the Clerk of said Court to the said Surveyor for record in his office.
D.C. Code § 6-402