Res judicata on a preliminary issue in legal-tax relations involving Municipal Tax authorities and taxpayers

Abstract

This article proposes to investigate the impact of the change promoted by the CPC/2015 regarding the res judicata incident on the preliminary question (§ 1, I to III, and § 2 of art. 503 of the Code of Civil Procedure). We will investigate the effects of the new discipline on the legal-tributary relations of continued treatment, that is, to what extent the decision on the preliminary question regarding the (in)validity of the tax base rule prevents the taxpayer and the Municipal Tax Authorities from relitigating on an identical issue. It will be shown, for example, that if the taxpayer challenges the enforceability of the tax credit by filing a tax debt annulment action (or a tax enforcement action), even if the request is demarcated in time (referring to a specific assessment), once it becomes final and unappealable, the decision on the preliminary question regarding that (in)validity is projected to the other fiscal years prohibiting the taxpayer and the Municipal Tax Authorities from reporting on it. This is an innovation of significant importance in the legal system, especially in the tax system, as it avoids the proliferation of lawsuits and the production of inconsistent decisions.