Contributions to the analysis of the diversity of impacts of complementary health care.

Summary We propose an original analysis of the impact of supplementary health insurance on the behaviour of workers and firms in the labour market. The first chapter explains theoretically the wage and health investment policies chosen by the firm when the latter only imperfectly observes the employee's health status and when the health investment can lead to productivity gains via a better health status. We show that both policies are dependent on the firm's productivity. The second chapter explains the reasons why the joint supply of supplements and wages differs according to the structure of the firm. We show that VSEs and more generally firms subject to greater financial constraints do not offer coverage, as this is generally linked to the employment contract of the highest paid employees. The third chapter empirically analyses the impact of complementary health insurance on workers' health status. Being covered (relative to being uncovered) does not significantly improve health status. Similarly, access to group coverage (relative to individual coverage) does not result in a significantly improved health status. The last chapter analyses the absenteeism behaviour of workers under the effect of group supplementary insurance. The presence of a group contract induces the presence of moral hazard on short work stoppages when the worker belongs to small firms with low compensation for work stoppages.