La thèse vise à définir le rôle de l'usage non seulement dans l'obtention du droit de marque par l'enregistrement, mais aussi, d'examiner le rôle de l'usage dans l'étendue de la protection des marques. Cet examen conduira donc à faire une distinction entre, d'une part, l’usage de la marque par le titulaire lui-même, ce qui concerne donc l’existence du droit de marque (première partie), et d'autre part, l'usage de la marque par des tiers, ce qui concerne l'exercice du droit de marque (deuxième partie). La première partie sera elle-même divisée en deux titres. Dans le premier titre, on examinera le rôle de l’usage sur l’existence du droit de marque, dans le deuxième titre, on examinera comment démontrer les effets de l’usage. La deuxième partie, sera, elle aussi, divisée en deux titres : le premier titre est consacré à l'usage qui provoque la confusion entre les signes, autrement dit la contrefaçon au sens strict, et le second titre est consacrée à l'usage qui entraîne un lien entre les signes, et constitue la contrefaçon au sens large. / The thesis aims at defining the role of the use not only in obtaining the right of mark by the registration, but also, to examine the role of the use in the scope of the protection of the marks.This examination will therefore lead to a distinction between, on the one hand, the use of the mark by the proprietor himself, which therefore concerns the existence of the trademark right (part one), and, on the other hand, the use of the mark by third parties, concerning the exercise of the trademark right (part two). The first part will be divided into two titles. In the first title, we will examine the role of the use on the existence of the right of mark, in the second title, we will examine how to demonstrate the effects of the use. The second part, will also be divided into two titles: the first title is devoted to the use that causes the confusion between the signs,in other words the infringement in the strict sense, and the second title is dedicated to the use which causes a link between signs, and constitutes infringement in the broad sense.

The diploma thesis deals with trademark protection in the system of Community and US law by using the scientific comparative method. The Community trademark is used as the comparatum and the federal trademark as the comparandum. The main goal of the thesis is the comparison of the EU and US perspective on the trademark as one of the subjects of industrial rights. To reach the set goal, the key aspects of the trademark protection are fully discussed in compared legal systems. The first part of the thesis represents the theoretical introduction into the field of trademarks. Here, the historical development is summarized, the evolvement of the single community protection together with principles of trademark protection in the USA are explained, completed by a summary of the sources of law in compared legal systems. In the main part of the thesis, the trademark in both legal systems is discussed, starting with the trademark definition according to both the Community and US law together with the key international treaties; followed by an explanation of different trademark types with an emphasis on non-traditional trademarks; right to trademark; Community and US trademark registration compared to the international registration; trademark use; and concluding with the rights the trademark holder possesses.