Mich. Comp. Laws § 124.30
The conditional transfer of property pursuant to a contract under this act takes place when the contract is filed in the manner required by this section. After the affected local units enter into a contract under this act, the clerk of the local unit to which the property is to be conditionally transferred shall file a duplicate original of the contract with the county clerk of the county in which that local unit, or the greater part of that local unit, is located and with the secretary of state. That county clerk and the secretary of state shall enter the contract in a book kept for that purpose. The contract or a copy of the contract certified by that county clerk or by the secretary of state is prima facie evidence of the conditional transfer.
MCL 124.30