La. R.S. 45:179

Except as provided for in R.S. 45:172(A)(4), no person engaged in the business of a common carrier or contract carrier shall purchase or use a registration certificate or license plate on any motor vehicle operated by him in conducting such business without presenting to the vehicle commissioner or the public official charged with the selling and issuing of license plates and registration certificates, a certificate from the Louisiana Public Service Commission certifying that he is entitled to use the license plate or registration certificate.