My dissertation explores different determinants of job search behavior in order to highlight some obstacles in the access to jobs, in particular among disadvantaged workers. The first chapter evaluates a collective counselling program for young workers from deprived neighborhoods. This program seems more effective in helping participants access a stable job. The largest effect is found among participants assigned to groups with peers who have relatively bad employment prospects. In the second chapter, I study how an information shock affects the job search of unemployed workers and their access to employment. My findings suggest that providing information to help disadvantaged job seekers target firms which have large short-term hiring need...