A public establishment for inter-municipal cooperation with its own tax system and its member municipalities may decide, by concordant deliberations of the deliberative body of the public establishment and of the municipal councils, adopted by a majority of at least two-thirds of the municipal councils of the member municipalities of the public establishment representing more than half of the population of the latter or by at least half of the municipal councils of the municipalities representing two-thirds of the population, to proceed with the unification of one or more of the following direct taxes: council tax on second homes and other furnished premises not used as a main residence, property tax on built-up properties, property tax on non-built-up properties.
For each tax for which unification is decided, the rate of the tax is voted by the deliberative body of the public establishment of inter-municipal cooperation within the same limits and conditions as those applicable to its vote by the communes.
In the first year of the unification provided for by this article, the rate of the tax on built-up properties or the tax on non-built-up properties for which unification has been decided may not exceed the average rate of this tax in all the member communes recorded in the previous year, weighted by the relative size of the bases of these communes.
In the first year of the unification provided for by this article, the rate of council tax on second homes and other furnished premises not allocated to the principal dwelling, if its unification has been decided, may not exceed the harmonised average rate of the member communes recorded in the previous year.
By way of derogation from the third and fourth paragraphs, when the public establishment of inter-municipal cooperation levied an additional tax the year preceding that of the unification provided for by these provisions, the average rate mentioned in the same third and fourth paragraphs is increased by the rate of the tax levied the previous year by this public establishment of inter-municipal cooperation.
The rate of the tax applicable in each member municipality is brought closer to the rate of the public establishment for inter-municipal cooperation until a single rate is applied, the difference being reduced each year in equal shares, in proportions depending on the ratio observed in the year preceding the first year of the unification provided for by this article between the rate of the least taxed municipality and that of the most taxed municipality.
Where this ratio is greater than 90%, the rate of the public establishment for inter-municipal cooperation applies from the first year. Where this ratio is greater than 80% and less than or equal to 90%, the difference is halved in the first year and eliminated in the second. The reduction is made by a third when the ratio is greater than 70% and less than or equal to 80%, by a quarter when it is greater than 60% and less than or equal to 70%, by a fifth when it is greater than 50% and less than or equal to 60%, by a sixth when it is greater than 40% and less than or equal to 50%, by the seventh when it is greater than 30% and less than or equal to 40%, by the eighth when it is greater than 20% and less than or equal to 30%, by the ninth when it is greater than 10% and less than or equal to 20% and by the tenth when it is less than or equal to 10%.