D.C. Code § 10-605
Seventy per centum of so much of said sum authorized by § 10-603 as may be expended as therein provided shall be reimbursed to the Federal Emergency Administration of Public Works from any funds in the Treasury to the credit of the District of Columbia, as follows, to wit: Not less than $1,000,000 on the 30th day of June each year after such sum shall have been advanced to said District until the full amount expended hereunder is reimbursed, without interest for the 1st 3 years after any such advances and with interest at not exceeding 4 per centum per year thereafter on annual balances as of each June 30th; provided, that whenever the District of Columbia is under obligation by virtue of the provisions of § 4 of Public Act No. 284, 71st Congress, entitled "An Act for the acquisition, establishment, and development of the George Washington Memorial Parkway, and so forth," approved May 29, 1930 (46 Stat. 485, ch. 354), to reimburse the United States for sums appropriated by the Congress under that Act, the total reimbursement required under both that Act and §§ 10-603 to 10-606 shall be not less nor more than $1,300,000 in any 1 fiscal year; provided, that the Mayor of the District of Columbia may, in his discretion, repay more than said amount; and provided further, that the Mayor may, in his discretion, allocate any reimbursement as between the sums due by him to the United States under the aforesaid Act and the sums due by him to the Federal Emergency Administration of Public Works under §§ 10-603 to 10-606; provided, that such sums as may be necessary for the reimbursement herein required of or permitted by the District of Columbia, and for the payment of interest, shall be included in the annual estimates of the Mayor of the District of Columbia, the 1st reimbursement to be made on June 30, 1936. Until 70 per centum of so much of said sum authorized by § 10-603 as may be expended as therein provided shall be reimbursed to the Federal Emergency Administration of Public Works, with interest as provided in this section, $.10 of the tax levied and collected upon each $100 of the assessed valuation of all real and tangible personal property subject to taxation in the District of Columbia shall be deposited in the Treasury of the United States to the credit of a special account for such reimbursement to the Federal Emergency Administration of Public Works and shall not be available for any other purpose. The Mayor may, in his discretion, anticipate from said special account the payments required by §§ 10-603 to 10-606; provided, that whenever the District of Columbia is under obligation by virtue of the provisions of § 4 of said Public Act No. 284, 71st Congress, reimbursement shall be not less than $300,000 in any 1 fiscal year.
D.C. Code § 10-605