D'un point de vue théorique , il s'agira de mobiliser des champs diversifiés de la recherche sociologique, tels que la sociologie urbaine, la sociologie du travail, ou encore de la formation, tout en proposant une mise en perspective socio-historique sur les politiques publiques d'orientation mises en place depuis les années 40-50. l'orientation, invoquée à cette période pour résoudre des problèmes d'emploi, dans un contexte marqué par une forte croissance industrielle et une pénurie de main d'oeuvre qualifiée apparait désormais comme un moyen d'adapter la main d'oeuvre à la flexibilité du marché du travail. ce retour vers le passé permettra de comprendre comment le présent s'est construit. / The lifelong guidance has become a commonplace of political discourses. It is presented as a way to unify a patchwork of organisms, stakeholders and ideas, and to equip people to face in the labor market. Structured through a plethora of legislative proceedings, this notion carries a vision of rational persons, able to take charge of their careers independently. This thesis questions the concrete forms of guidance, at a time when its access throughout life is enshrined as a right, an,d the continuity it preaches given to obvious. This work intends to combine what disciplinary boundaries deal separately; it proposes a joint analysis of the orientation in educational and professional contexts. The three levels of interaction apprehended (national, local, individual) lead us to confront political wills, translations of these injunctions operated by local actors, and experiences of targeted audiences, both in the educational and professional spheres. We speculate that lifelong guidance is become an organizing principle of professional life. However, we believe this approach can be a powerful vector of inequalities, people being unequally able to successfully anticipate and project themselves, to the image of that request the orientation process.