Mich. Comp. Laws § 123.1395

Sec. 15. Subject to sections 5 to 8 and 11, this act does not prohibit a local governmental body from adopting, enforcing, or administering an ordinance, local policy, or local resolution that provides for the terms and conditions of a voluntary agreement between an employer and the local governmental body in connection with the provision of services directly to the local governmental body or in connection with the receipt of a grant, tax abatement, or tax credit from the local governmental body.