Any officer of the city, or any department thereof, who shall aid or assist a bidder in securing a contract to furnish labor, material or supplies at a higher price than that proposed by any other bidder, or who shall favor one bidder over another by giving or withholding information, or who shall wilfully mislead any bidder in regard to the character of the material or supplies called for, or who shall knowingly accept materials or supplies of a quality inferior to those called for by the contract, or who shall knowingly certify to a greateramount of labor performed than has been actually performed, or to the receipt of a greater amount or different kind of material or supplies than has been actually received, shall be deemed guilty of malfeasance and shall be removed from office.