L'àmbit de la Tesi doctoral descansa en l'anàlisi de l'esperit i la praxis del procés prejudicial, centrant-lo en la fase final de l'anomenat procés, els efectes de la sentència del Tribunal de Justícia i la subsegüent aplicació per les jurisdiccions nacionals en la resolució del procés intern.La primera part de la Tesi doctoral (capítols I a III) s'ha centrat en l'estudi dels efectes jurídics de les sentències prejudicials d'interpretació, analitzant els tres principals temes que es susciten, a saber, els seus efectes jurídico-processals, els seus efectes jurídico-materials i la seva dimensió temporal.En la segona part (capítols IV a VII) es va emprendre el tema des del prisma diferent de les posisions de jurisdiccions nacionals davant les sentències perjudicials, el comportament del qual, acatant o incumplint-les, corrobora o nega de manera evident el que s'ha afirmat en els tres primers capítols. / El ámbito de la Tesis doctoral descansa en el análisis del espíritu y la praxis del proceso prejudicial, centrándolo en la fase final de dicho proceso, los efectos de la sentencia del Tribunal de Justicia y su subsiguiente aplicación por las jurisdicciones nacionales en la resolución del proceso interno.La primera parte de la Tesis doctoral (capítulos I a III) se ha centrado en el estudio de los efectos jurídicos de las sentencias prejudiciales de interpretación, analizando los tres principales temas que se suscitan, a saber, sus efectos jurídico-procesales, sus efectos jurídico-materiales y su dimensión temporal.En la segunda parte (capítulos IV a VII) se abordó el tema desde el prisma diferente de las posiciones de jurisdicciones nacionales ante las sentencias prejudiciales, cuyo comportamiento, acatando o incumpliéndolas, corrobora o niega de manera evidente lo afirmado en los tres primeros capítulos. / The Doctorship Thesis lies in the analysis the spirit and the practice of the preliminary process, focusing it in the final stage of such process, the effects of the Court of Justice sentence and their subsequent enforcement by the national jurisdictions in the internal process of the resolution.The first part (chapters I to III) has been focused in the study of the legal effects of the interpretative preliminary rulings, analysing the three main subjects that are issued, i.e., their juridical procedural effects, their juridical material effects and their temporary dimension.In the second part (chapters IV to VII) the issue was laid down from the different point of view, the positions kept by the national jurisdictions, which behaviour, accepting or refusing the preliminary ruling, acknowledges or denies in a clear way what it was assessed in the first three chapters.

Dégagés de façon prétorienne par la Cour de justice, les principes généraux du droit de l’Union occupent dans la jurisprudence administrative française une place que peut expliquer la notion de dédoublement fonctionnel. D’une part, ce sont des normes obligatoirement appliquées par le juge national dans le champ du droit de l’Union.D’autre part, en dehors du champ, ils constituent une source d’inspiration pour le Conseil d’Etat dans la création et l’interprétation des principes généraux du droit français. Dans le premier cas, le juge administratif est garant du respect de ces principes.Fidèle aux exigences de la Cour de justice, il assume pleinement son rôle de juge de droit commun de l’application des principes du droit de l’Union. Dans le second cas, il devient acteur de la circulation des principes en Europe. Toutefois la coexistence des principes peut engendrer des tensions, accentuées par la difficulté à délimiter le champ du droit de l’Union, incertain et en pleine expansion. C’est pourquoi la thèse propose le déploiement d’une politique jurisprudentielle de convergence, dans laquelle le juge administratif affirmerait explicitement son souci de s’inspirer des principes du droit de l’Union. Ces derniers, combinés avec les principes issus de la Charte des droits fondamentaux, de la CEDH et des ordres nationaux, semblent donner naissance à une nouvelle catégorie de source matérielle : les principes européens communs. L’originalité de celle-ci, qui la différencie de toute autre source, est de constituer une oeuvre collective des juges en Europe, dans laquelle ces derniers puisent leur inspiration pour créer de nouveaux principes ou interpréter les principes existants. / The general principles of EU law, which are a judicial creation of the Court of Justice, play a role in French administrative case law that can be explained by the notion of functional duplication (“dédoublement fonctionnel”). On the one hand, the general principles of EU law are rules that are mandatorily applied by the national courts within the scope of EU law. On the other hand, beyond that scope, they constitute a source of inspiration for the Conseil d’Etat in creating and interpreting general principles of French administrative law. In the first case, the administrative courts are the primeguarantors of compliance with these principles. In line with the requirements of theCourt of Justice, they entirely fulfill their role as the ordinary courts applying principles of EU law. In the second case, they become one of the protagonists of the movement of principles in Europe. However, the coexistence of principles could trigger tensions,heightened by the difficulties in delineating the scope of principles of EU law, which is uncertain and rapidly expanding. That is why the thesis proposes the development of a judicial convergence policy, in which the administrative courts would more clearly affirm their concern to take inspiration from the general principles of EU law. These latter, combined with the principles stemming from the Charter of Fundamental Rights,the ECHR and the national orders, seem to give rise to a new category of material source: the common European principles. The originality of this category, which differentiates it from any other source, is that it constitutes a collective work of judges inEurope, from which they draw their inspiration to create new principles or interpret the existing ones.

1 Abstract This dissertation deals with investment protection in the European Union from several points of view. The first part deals with the history of investment protection and its main basis and grounds for current legislation and proposals for future regulation, particularly within the EU. In subsequent parts, current legislation and intra-European Union investment protection is analysed in detail, including the question of validity and applicability of Intra-EU BITs, i.e. bilateral treaties concluded between two EU Member States. The analysis is made from the perspective of EU law, as well as from the point of view of public international law. The dissertation further deals with their relationship and demonstrates contradictions between them in two crucial cases, Eureko/Achmea and Micula. Additional themes of this dissertation are the powers of the European Union regarding investment protection and the conclusion of international treaties such as CETA and TTIP. This dissertation further deals with the status, jurisdiction and functioning of the International Centre for Settlement of Investment Disputes (ICSID), demonstrating the relatively smooth and widely accepted investment dispute settlement mechanism. In this regard, the proposed EU Multilateral Investment Court project in analysed, including a...