The warrant, after its delivery to the contractor or his assigns, shall constitute full authority to the contractor, his agent or assigns, to collect the said assessments, and they shall be free to make demands upon the owners by virtue of said warrant and to receive payment of said assessments and give receipts therefor. The warrant shall be returned to the Department of Public Works after its delivery to the contractor, or his assigns, with the written statement of all payments received upon the assessment, signed by the contractor, or his assigns, or some person on his or their behalf, and stating whether any of the assessment remains unpaid in whole or in part and the amount thereof. If the assessment is payable in installments as provided in Sections 225 to 236, inclusive, of this Article, then the fact that a bond has been given for such assessment shall be stated if such shall have been given. Thereupon the said Director shall cause the return so made to be recorded with the record of the warrant and assessment.