Section 172. Property to be assessed at fair cash value -- Punishment of assessor for willful error.

All property, not exempted from taxation by this Constitution, shall be assessed for taxation at its fair cash value, estimated at the price it would bring at a fair voluntary sale; and any officer, or other person authorized to assess values for taxation, who shall commit any willful error in the performance of his duty, shall be deemed guilty of misfeasance, and upon conviction thereof shall forfeit his office, and be otherwise punished as may be provided by law.