If any assessment shall remain in arrears for more than six months after confirmation, suit may be brought for its collection with interest and costs, and the commission may proceed to advertise the real estate upon which the assessment may be a lien to be sold at public auction at the courthouse of the county, on a day not less than two months distant, between two and five o’clock in the afternoon. Such advertisement shall be published at least once each week for a period of at least three weeks next preceding the sale, in two of the newspapers published and circulating in the county, and shall be the only notice required. It shall contain the names of the owners of real estate in default, if the same be known, and if not known shall state the names of owners to be unknown, and shall give the amounts due from them respectively, with a short description of the real estate to be sold.