Mich. Comp. Laws § 15.325

Sec. 5. (1) This act is aimed to prevent public servants from engaging in certain activities and is not intended to penalize innocent persons. Therefore, no contract shall be absolutely void by reason of this act. Contracts involving prohibited activities on the part of public servants shall be voidable only by decree of a court of proper jurisdiction in an action by the public entity, which is a party thereto, as to any person, firm, corporation or trust that entered into the contract or took any assignment thereof, with actual knowledge of the prohibited activity. In the case of the corporation, the actual knowledge must be that of a person or body finally approving the contract for the corporation. All actions to avoid any contract hereunder shall be brought within 1 year after discovery of circumstances suggesting a violation of this act. In order to meet the ends of justice any such decree shall provide for the reimbursement of any person, firm, corporation or trust for the reasonable value of all moneys, goods, materials, labor or services furnished under the contract, to the extent that the public entity has benefited thereby. This provision shall not prohibit the parties from arriving at an amicable settlement. (2) Negotiable and nonnegotiable bonds, notes or evidences of indebtedness, whether heretofore or hereafter issued, in the hands of purchasers for value, shall not be void or voidable by reason of this act or of any previous statute, charter or rule of law.