No manufacturer or distributor or importing distributor or foreign importer shall enter into any contract with any person licensed to sell at retail whereby such licensee agrees not to sell any alcoholic liquors manufactured or distributed by any other manufacturer or distributor or importing distributor or foreign importer, and any provision in any contract violative of this Section shall render the whole of such contract void and no action shall be brought thereon in any court. However, nothing in this Section shall prohibit the Department of Agriculture from entering into contracts for exclusive facilities upon the State Fair Grounds on an equal basis.
235 ILCS 5/6-23