This study addresses the effectiveness and impact of immersion programmes at two distinct French Language Institutions: the NFLV in Badagry, Lagos Nigeria and the IUP in Porto Novo, Benin Republic. The problem under investigation is the comparative effectiveness of the immersion programme offered by NFLV and IUP. Specifically, the study identified and evaluated differences in programme design, pedagogical strategies, students’ outcomes, and the level of availability of human and material resources between these two Institutions. The study used cluster sampling design to select 100 students who served as participants for the study. Descriptive survey design was adopted and a well-structured questionnaire was the main instrument used for collecting data in the course of the study. The data collected was analysed using simple percentages, mean/standard deviation descriptive statistical tools and independent t-test for significance difference between two means was equally tested. The result showed that the Human and Material resources for immersion programmes in the NFLV and IUP is moderate. This is because of the grand mean scores of 2.96 and 3.14 are within the mean range interpretation of moderate high and are above the criterion mean of 2.50 for a four point likert scale rating. Although, better in IUP Porto Novo, since the grand mean of 3.14 is greater than 2.96 which represents NFLV. The programme design, pedagogical strategies, students’ outcomes were found to be better in IUP since their environment is a naturally francophone country, which provides a more immersive linguistic experience. Independent t-test for difference between means led to upholding of the null hypothesis that there is no significant difference between the effectiveness of NFLV and IUP centres for immersion programme. The study recommended inter alia that; leveraging on technology can enhance language learning. The NFLV should invest in digital resources such as language learning apps, virtual reality experiences, and online French speaking forum to complement traditional teaching methods.