This thesis is a collection of independent essays in applied microeconomics. In the first chapter, I investigate if growing up in an ethnic enclave slow down the adoption of natives cultural behaviour by immigrants. To measure cultural behaviour, I use administrative data on usage of contraceptives by women aged 15 to 20. To observe exogenous variation in the ethnic concentration of (close) neighbourhoods, I rely on the random allocation of asylum seekers to government run accommodation in the Netherlands during the period 1996 to 2012. Although behaviours do converge with time, neighbourhood ethnic composition has no effect on this process. In the second chapter, co-authored with Eva Johansen, we study if teenagers decision to use contraceptives is influenced by peers. To identify peer effects, we rely on cross-cohort variation in students usage in Danish high-schools. To address the reflection problem, we focus on the influence of older cohorts on younger ones. Contraception not being prevalent among young women with a non-Western background, its usage is a good measure of cultural adaptation. Looking at the effect of different peers group is indicative of which is influential. Immigrant teenagers adapt their behaviours to what other immigrants (but not what other natives) do. Their probability of using contraceptives and of having an abortion becomes lower, but not their likelihood of being treated for chlamydia. In the third chapter, I study the influence of pre-migration social background on the economic assimilation of immigrants. I use unique French survey data to trace family histories over three generations, both in the sending country before migration and later in France. Pre-migration socioeconomic status is key in explaining the educational achievements of second generation immigrants. Holding the origin country fixed, it is as important as father's occupation in the destination country. After an initial loss at migration, the first generation regains human capital more slowly than the second generation develops its own. In a simple model of human capital accumulation, this can be due to (i) parents investing more in their children than in themselves or (ii) the productivity of the two investments being different. The latter channel is supported empirically.