No warrant for the payment of any claim shall be issued by the Director of Finance until such claim shall have been approved by the director of the department for which the indebtedness was incurred and by the Mayor. And such officers and their sureties shall be liable to the Municipality for all loss or damage sustained by the Municipality by reason of the corrupt approval of any such claim against the Municipality. Whenever any claim shall be presented to the Director of Finance, he shall have power to require evidence that the amount claimed is justly due and is in conformity to law and ordinance and for that purpose he may summon before him any officer, agent or employee of any department of the Municipality, or any other person, and examine him upon oath or affirmation relative thereto.