Essays on risk management in the presence of ambiguity.

Summary The thesis aims to establish optimal technology risk management to ensure hazard reduction of new emerging risks, without impeding the innovation pathway. The research contributes to ex-ante and ex-post risk management strategies and provides theoretical and empirical evidence to address the management of new emerging risks. The first part of the thesis examines, from a legal and economic perspective, the effectiveness of the rule of civil liability when the decision-maker lacks information about the probability of an event. The second part of the thesis pays particular attention to the energy transition in France to focus on the insurability of energy performance in the housing sector. The theoretical and experimental results of the first part of the research attest to a strong empirical validity that tort law cannot provide optimal ex-ante incentives in the absence of information on the probability of an accident. Both unlimited and limited liability regimes lead to an overinvestment in prevention relative to newly emerging risks. The empirical results of the second part of the thesis reveal that 23.75% of the households, which participated in the renovation program "Je Rénove BBC", cannot reach the expected energy target, but the magnitude of the energy performance gap is relatively small. The research results imply several policy recommendations for managing new emerging technologies in the future.