Real property acquired, developed, improved, restored or rehabilitated by a municipality pursuant to subdivision four of section 52-0901 of this title with funds made available pursuant to this title shall not be sold or disposed of or used for other than public park purposes without the express authority of an act of the legislature, which shall provide for the substitution of other lands of equal fair market value and reasonably equivalent usefulness and location to those to be discontinued, sold or disposed of, and such other requirements as shall be approved by the commissioner.