In school year 2018/2019, 127 first graders participated in the innovative bilingual program "Bilinguale Grundschule Französisch" in Bavaria. In this program the pupils are taught both in French and in German in subjects as mathematics, science, physical education, music and art right from the start. This project is of great research interest since there are very few state-run bilingual programs in primary schools in Germany that consider other foreign languages than English. As a consequence, the presented bilingual program – which is accompanied by our research team on a methodological, curricular and empirical level – is accessible to heterogeneous groups of learners. Hence the presented empirical study focuses on the following key research questions: 1) Which level of competence in French is achieved in listening comprehension, silent word reading fluency and monological-descriptive speaking after the first school year? 2) Which level of competence in reading comprehension in German on the one hand and in general mathematical competences on the other hand are reached by the pupils taking part in the program? 3) Are there any significant differences according to the intersectionality axes of gender, multilingualism and socioeconomic background and if so, in which manner could these differences be described and interpreted? In order to answer these research questions, a wide test battery was employed, including cognitive base-line tests (cf. Raven 2001), standardized tests for German (cf. Lenhart et al. 2018) and mathematics (cf. Krajewski et al. 2002), independently developed tests for the French skills, which respond to the curriculum and also to the CEFR and which have been elaborated for the program. Furthermore, questionnaires for the parents and for the teachers were used in order to get more background information. In line with the empirical results, adequate practices of responding on pupils’ various backgrounds in research will be discussed.