No member of Council or City employee shall take any official action on any contract or other matter in which he has any direct or indirect financial interest other than the common public interest. Any willful violation of this section shall constitute malfeasance in office, and any member of Council or employee of the City found guilty shall thereby forfeit his office or position. Any violation of this section with the knowledge, express or implied, of the person or corporation contracting with the City shall render the contract voidable.