Orphan works restrict new uses allowed by digital technologies. Indeed, an orphan work is a work that is protected and disclosed and whose right holders cannot be identified or located, despite due diligence. So they raise the traditional economic dilemma posed by intellectual property: Should we favour right holders through exclusive monopolies, or give priority to the spreading of culture and knowledge? In a Law and Economics perspective we wonder what legislative changes could lead to optimal solutions. We first present the risks of economic inefficiency current legislation has resulted in, such as the loss of social well-being and the importance of transaction costs, and estimate the ratio of orphan works in France. We then summarize the different expectations of market actors with regard to optimal use of these works so as to better analyse the field of possible scenarios, taking into account both economic and legal constraints.