Mich. Comp. Laws § 123.843

Sec. 3. Any officer or employe or agent of such municipality who shall require any employe or other person in any such fire department, save as hereinbefore excepted in section 2 of this act, to be on duty in such employment for a longer time than that hereinbefore provided, or to be off duty for a lesser time than that hereinbefore provided, shall be guilty of a misdemeanor and on conviction thereof shall be punished by a fine of not more than 100 dollars or by imprisonment in the county jail for not more than 3 months, or by both such fine and imprisonment.