A city of the metropolitan class shall provide for the manner in which regulations and restrictions adopted pursuant to sections 14-401 to 14-418 and the boundaries of districts created under section 14-402 shall be determined, established, and enforced, and from time to time amended, supplemented, or changed. The city shall not determine the boundaries of any district or impose any regulations or restrictions until after the appropriate planning board of the city has made recommendations on such regulations, restrictions, or boundary changes, and no such regulation, restriction, or boundary change shall become effective until after a public hearing at which citizens shall have an opportunity to be heard. At least one day's notice of the time, place, and purpose of such hearing shall be published in the official newspaper or a legal newspaper in or of general circulation in such city, and not less than ten days before such hearing.