The paper focuses on a comparison of full- and part-time schooling in Germany with regard to expected linguistic differences in the performance of students with a migrant background and students with a non-migrant background. This topic is of major interest since the number of full-time schools in Germany increased in the last decade. Associated with this expansion are political and academic expectations to improve the moderate PISA results of German students. Another aspect of implementing full-time schools is to reduce social inequality which, according to large-scale assessments (PISA, TIMSS, and the like), seems to be one major problem of the German educational system. Especially students with migrant background are largely overrepresented in lower school tracks and hence show the lowest rates of employment after leaving school. To identify possible benefits of full-time schooling a longitudinal study with students of primary and secondary schools in Hamburg, Bavaria and Baden-Wuerttemberg is being conducted (N appr. 3.500). The presentation will present results from the first wave of the data. It will include an outlook on a part of the project which contains a comparative perspective with schools in France.