In addition to any civil penalties assessed against the landowner, open space land which has been classified as restricted land pursuant to this chapter but which has been developed or put to a use either exercising any reserved rights to develop or violating its restricted classification shall be subjected to a penalty in addition to the annual real estate tax imposed upon such property of 10 percent of the full and true value of the portion of said land on which an inconsistent use has occurred as prescribed by N.H. Rev. Stat. § 75:1 without regard to the restriction. The penalty shall become due and payable to the municipality as of the date of the inconsistent use. Such developed land shall no longer qualify for assessment as restricted land under this chapter.