In this thesis, I study the impact of minimum wage policy and city agglomeration on wages and employment in local labour markets. This is an important topic because having a better understanding of the determinants of regional wage differentials and employment offers insights into: the roles played by local production, consumption and city structures; the standard of living enjoyed by workers with different human capitals; and policy recommendations for the future minimum wage law and city planning regulations. I use local occupation and geographic information to assess how highly productive occupations and local consumption amenities sort workers and generate local wage differentials. I also use this information to construct instruments that enable the accurate estimation of the effects of policy interventions. After an introduction in chapter 1, chapter 2, The Impact of the Minimum Wage on the Wage Distribution: Evidence from China, provides an empirical estimation of the effects of minimum wages using a Chinese household survey. I introduce new instrumental variables, relating to transport costs and local productivity, to control for the potential median wage endogeneity. The instrument variable regressions indicate that the effective minimum wage, defined as the ratio between the minimum wage and the median wage, significantly reduces the lower tail wage inequality — measured by the wage differential between the 50th and the 10th percentiles— by up to 0.3 per cent. In chapter 3, The MinimumWage and Its Impact onWage and Employment, joint work with Coen Teulings, we propose a novel framework for estimating the effects of minimum wages by considering the neoclassical wage and labour participation equations at the same time. To estimate the non-linear censored model with correlated error terms, we provide a five-step procedure and use maximum likelihood estimation. After correcting the bias using occupation information and city size, we find that effective minimum wage correlate significantly with the proportion of workers earning below minimum wage. I study the structure of city and commuting in chapter 4, Consumer City and the Sharing Economy. Based on the international trade literature, I develop a theoretical model with multiple cities, which have different amenities and productivities. In equilibrium, the unobservable parameters are estimated using local employment, wage, and commuting information. Cities show strong agglomeration effects in both productivity and consumption amenities. A counterfactual technological improvement, providing a cheaper transportation for workers and consumers, leads to a more concentrated employment distribution, commuting pattern and higher utility. In the final chapter, Agglomeration and Sorting, joint work with Coen Teulings, we show that agglomeration externalities are strongly related to the occupational structure. At the same time, regional differences in house prices offset these externalities. We develop a multi-region model with regional heterogeneity in workers and jobs, tradable versus non-tradable commodities, consumption amenities, regional house prices, non-homothetic utility, and interregional labour mobility. The model fits the regional data on the fixed wage effects, the return and mean level of human capital, land prices, and the city-rural area distinction well. We use land values to calculate the value of agglomeration.

Les entrepreneurs n’ont pas manqué de soulever l’importance et la nécessité d’une structure européenne flexible pour répondre aux besoins des PME. En effet l'introduction d'une société à conception contractuelle dans le droit européen revêt de multiples intérêts. D'une part, elle intègre les PME dans la continuité du processus de construction du marché intérieur. D’autre part, elle offre une liberté d’action appréciée par les entrepreneurs qui évoluent dans un marché fortement concurrentiel. Enfin, le caractère contractuel permet au législateur européen de revenir sur la définition des libertés d'établissement et de circulation des capitaux.Aussi encourageant que soit ce projet, il n'en demeure pas moins source d'interrogations et d'inquiétudes. La liberté contractuelle comporte des risques si elle n'évolue pas dans un cadre juridique adapté et protecteur. Cette thèse a pour objectif d’analyser les effets de la transposition de la liberté contractuelle dans le droit européen des sociétés. Pour comprendre la portée de l’adoption du texte relatif à la SPE, cette thèse tentera de définir la liberté contractuelle au sens communautaire, de souligner ses avantages et d’analyser ses inconvénients. / Entrepreneurs consider flexible structures are important to meet European SMES needs. Indeed, the transposition of a contractual company in the European law are very valuable. On the one hand, it includes SMES in the process of construction of internal market. On the other hand, it offers to entrepreneurs a freedom to manage their companies in order to be more competitive. Finally the contractual aspect of the company allows the European parliament to reconsider the definition of freedom of establishment and free movement of capital. As encouraging as this project is, it remains a source of questions and concerns. Contractual freedom could involve risks if it doesn’t evolve in a suitable protective legal framework. This thesis aims to analyze the effects of the transposition of contractual freedom in the European company law. To understand the scope of the adoption of the text relating to the SPE, this thesis will try to define the contractual freedom in EU terms, to emphasize its advantages and disadvantages analyzed