Privacy protection is part of the social demand, which is rendered more crucial by the introduction of new technologies of information and communication in the workplace. Indeed, they improve the capacities of traditional systems for control and offer new ways to monitor (cybersurveillance) and to collect personal data. ?Big Brother is Watching? can illustrate the perceptions about the workplace of numerous employees. Can we reconcile privacy protection of employees with the enterprise?s needs ? This article is mainly devoted to the legal aspects of this theme, in French organizations. First of all, we study why it is impossible to establish a tight frontier between an employee?s private life and his/her professional life. The main reason is that we are not able to determine precisely the outlines of the sphere of personal life. The notions of ?privacy?, ?private life? and ?personal life? are extremely vague and variable in legal literature. We propose an original characterization of the notion of ?personal life?, in terms of ?dominant logics? : the logics of self-determination and of informational control on personal data. Next, we explore the economic stakes of the right to privacy with respect to employment relationships : what are the economic consequences of its respect, as regards secrecy and liberty ? We start with the economic analysis of privacy as made by Posner, Hirshleifer and Rosenberg. These authors study the right of privacy in terms of ?informational asymmetry?, and they get back to Akerlof?s demonstration of the risk of adverse selection during the phase of recruitment. The right to privacy seems to produce economic costs. After having exposed the responses given by the jurisprudence during the last fifteen years and by the laws in France, we establish a critical analysis of French legal principles. Firstly, they permit to reduce informational asymmetry if there is a risk of inefficiency. Secondly, when they protect personal life, legal rules appear as an help to make rational decisions in selecting only relevant information. Further on, we explore the ?post?-contractual phase of the work relationship once the employment contract has been concluded. To respect employees? personal life implies to reduce monitoring and to give them autonomy and trust. ? On the one hand, if we adopt the agency theory point of view, the respect of personal life can be seen as a source of moral hazard (post-contractual opportunism) because of the informational asymmetry. But we show that this analysis is hold up by hypotheses of extrinsic, amoral and asocial motivations of employees. ? On the other hand, if we adopt the self-determination theory as developed in applied psychology, the respect of personal life can be seen as a source of self regulated motivations (intrinsic, moral and pro-social motivations) and high task involvement. We conclude that when the work situation permits and requires self regulated motivations, managers should choose high levels of respect for privacy. However, when only extrinsic, amoral and asocial motivation can emerge from a work design, managers should be allowed to reduce such respect. What are the answers under French law ? We find considerable uncertainty to exist as regards an employee?s right to autonomy. This has broad economic consequences : managers can choose between optimal levels of monitoring and incentives or simply trust and grant autonomy. In others words, they have the legal possibility to choose between different levels of respect of the employees? personal life. Nevertheless, a set of legal rules determines legal practice : restriction of liberties, activities for monitoring and informational searches about employees must satisfy principles of transparence, proportionality and relevancy.