I. – 1 New constructions and changes in the consistency or use of built and unbuilt properties, as well as changes in the use of the premises mentioned in I of article 1498 and factors likely to modify the method of determining the rental value pursuant to articles 1499-00 A or 1500. The same applies to changes in the physical characteristics or environment.
The communes and the public establishments for inter-communal cooperation with their own tax status may, by a concordant decision taken under the conditions provided for in I of article 1639 A bis, limit the increase in the rental value of premises used for residential purposes determined in accordance with article 1496 when this increase results exclusively from the observation of changes in the physical characteristics or environment and is greater than 30% of the rental value for the year preceding the year in which these changes are taken into account.
The increase in the rental value referred to in the second paragraph is retained at the rate of one third in the first year, two thirds in the second year and in full from the third year following that in which the changes are noted.
The decision must be taken by all the municipalities and public establishments for inter-municipal cooperation with their own tax system that levy a tax based on the property rental value of the premises for which the changes referred to in the second paragraph have been noted.
2. When an undeveloped property becomes liable to property tax for the first time or after having temporarily ceased to be liable, it is assigned an assessment.
II. – 1. The rental values resulting from the changes mentioned in I of this article are assessed:
a) For premises used as a dwelling or for home-based paid employment, according to the rules set out in articles 1496 and 1497, on the reference date of the previous general review ;
b) For property assessed according to the rules provided for in II of article 1498, on the date mentioned in A of the same II;
c) For property assessed according to the rules provided for in III of article 1498, on the date mentioned in B of the same III.
However, industrial fixed assets subject to property tax on built-up properties are, regardless of the date of their acquisition, valued by the administration based on their cost price in accordance with the provisions of article 1499, where they are included as assets in the balance sheet of their owner or operator and the latter is subject to the obligations defined in article 53 A. The local direct tax commission is kept informed of these assessments. When an intermunicipal direct tax commission is set up, it is kept informed of these assessments instead of the communal commissions.
2. With regard to undeveloped properties, these values are determined according to the rates set for properties of the same type existing in the municipality or, if there is no such rate, according to a rate established for this purpose.