Section 56A. The words ''municipal light commission'' as used in this section and in sections fifty-six B to fifty-six E, inclusive, shall mean a light commission, gas and electric commission or similar body established by act of the legislature and vested with all powers and duties formerly exercised by the mayor and selectmen under this chapter, and with the powers and duties conferred upon municipal light boards under this chapter.

No member of a municipal light commission or manager thereof shall directly or indirectly make a contract with the city or municipal lighting plant or receive any commission, discount, bonus, gift, contribution or reward from or any share in the profits of any person making or performing such contract unless such member or manager immediately upon learning of the existence of such contract, or that such contract is proposed, shall notify in writing the municipal light commission or city of the nature of his interest in such contract and shall abstain from doing any official act on behalf of the commission or plant in reference thereto.

A violation of any provision of this section shall render the contract in respect to which such violation occurs voidable at the option of the commission. Any person violating the provisions of this section shall be punished by a fine of not less than fifty nor more than one thousand dollars or by imprisonment for not more than one year, or both.

This section shall not apply to contracts of employment between a municipal lighting plant and its manager.

This section shall not apply to contracts between the city or municipal lighting plant and a corporation of which the member or manager is a stockholder or bondholder, unless the member or manager or a member of his immediate family owns or controls more than one per cent of the capital stock or more than one per cent of the outstanding bonds of such corporation.