La. Revenue and Taxation § 47:1963
Where immovable properties are assessed under a single assessment, without segregation of the respective assessments of the properties involved, if any part of the properties so assessed is subject to a conventional mortgage, and the nature of the assessment is such as to make it impossible to determine what part of the assessment is chargeable to the property mortgaged, and what part is chargeable to the remainder of the properties, the tax assessors of the parish wherein lies the mortgaged property, upon receipt from any mortgagee, or the holder or holders of a note or notes identified with the act of mortgage, of a written request containing an accurate description of the property subject to the mortgage and a reference to the mortgage records of the parish where the mortgage has been recorded, shall separately describe the property so mortgaged, and shall separately assess it with its equitable share of the total tax involved. The purpose of this provision is to place a mortgagee, or any holder or holders of such mortgage notes in a position to protect their mortgage rights against tax delinquencies, without paying taxes on any property other than the property subject to their mortgage.
Any change in assessment that may be necessitated by these provisions shall apply only to tax rolls compiled and filed after receipt of the prescribed notices.
Where these provisions have been complied with by a mortgagee, or any holder or holders of such mortgage notes, any assessment thereafter made which is not in conformity with these provisions shall be null and of no legal effect whatever.
La. Revenue and Taxation § 47:1963