Section 13. The provisions of sections five to eleven, inclusive, shall, except as provided in section fourteen, apply to all legal holidays, except January first, the third Monday in January, the third Monday in February, March seventeenth, the third Monday in April, May twentieth, June seventeenth, the second Monday in October after the hour of twelve noon, and November eleventh after one o'clock post meridian, or on the day following when any of said days occur on Sunday.
Any retail establishment which operates on January first, or November eleventh, the second Monday in October, under the exemption granted by this section, shall pay to those employees working on any of said days, time and one-half, or such larger sum as may be determined by contract; such work shall be voluntary and refusal to work for any retail establishment on such legal holidays shall not be grounds for discrimination, dismissal, discharge, reduction in hours, or any other penalty. The provisions of this paragraph shall be enforced by the attorney general. The provisions of section one hundred and eighty A of chapter one hundred and forty-nine shall apply to any violation of this paragraph.