The property acquired or held pursuant to this act is declared to be public property used exclusively for essential city, municipal public and governmental purposes and such property shall be exempt from all special assessments of the state or of any state public body. In lieu of taxes on such property a municipality or authority shall agree to make payments to the state or a state public body (including itself) as it finds consistent with the maintenance of the low-rent character of housing projects and the achievements of the purposes of this act.