Evasion of payment or the willful refusal on the part of any person to pay taxes over to the Director as required by this subtitle shall be a misdemeanor and upon conviction the person is subject:to imprisonment not exceeding 12 months or to a fine not exceeding $1,000, or both; and additionally, to a civil penalty of 100% of the amount of the assessment, in addition to the actual assessment provided by this subtitle. Willful refusal is evidenced by failure to pay the full amount due within 15 days of the date of the assessment. City Code, 1976/83, art. 28, §81 Ord. 86-687