Tenn. Code § 67-6-406
The commissioner is authorized to require the assistance of any official of the state or of any political subdivision thereof in the administration of this chapter, and it is unlawful for any official of this state or of any political subdivision thereof to accept an application for a certificate of title to a motor vehicle as provided for in title 55, chapters 1-6, or for a certificate of registration for a vessel as provided for in title 69, chapter 9, unless the applicant presents evidence that a sales or use tax, as provided for in this chapter, has been paid on the sales price of the vehicle or vessel by such applicant, or such applicant has authority from the commissioner to file an application for such certificate of title or registration without the payment of the sales or use tax. It is also unlawful for any official referred to herein to accept an application for a certificate of title to a motor vehicle when the sale of such vehicle constitutes an occasional and isolated sale which is taxable under § 67-6-102(8)(C), unless the applicant presents a bill of sale which evidences the sale price and also presents evidence that the sales or use tax has been paid on that amount, or in the absence of such a bill of sale, unless the official requires evidence of payment of the sales or use tax on the fair market value of the vehicle as the fair market value is determined by the official by reference to the most recent issue of an authoritative automotive pricing manual, such as the NADA Official Used Car Guide, Southeastern Edition.
T.C.A. § 67-6-406