No official, department or agency shall, during any budget or fiscal year, expend or contract to expend any money or incur any liability, or enter into any contract which by its terms involves the expenditure of money on behalf of the City for any purpose, in excess of the amounts appropriated for such expenditures or obligations. Any such obligation, oral or written, made in violation hereof shall be void. The officer or employee who knowingly attempts or purports to create such an obligation shall be guilty of a minor misdemeanor and upon conviction thereof shall be removed and shall be disqualified from holding further office or employment with the City. However, nothing in this section shall prevent the making of contracts not to be fully performed within the fiscal year when specifically authorized by Council.