Introduction – A majority of people diagnosed with HIV in France in 2022 were born abroad, but previous studies have suggested that a significant proportion of these infections occur after migration. Methods – In this study, we applied a mathematical model to data from mandatory HIV reporting (DO) in France to estimate the proportion of infections occurring after arrival in France among people born abroad who were diagnosed with HIV in France. We estimated this proportion annually between 2012 and 2022 based on mode of transmission, place of birth, and region of residence. Results – Overall, we estimate that 45% of people born abroad who discover their HIV status in France were infected after arriving in the country. This proportion is lower among those infected through heterosexual intercourse (approximately 40–45% depending on the year of diagnosis) and those born in sub-Saharan Africa (approximately 40%). It is higher among men who have sex with men (approximately 60%) and among people born in geographic areas other than sub-Saharan Africa, the Americas, or Europe (approximately 65%). The regions of residence where this proportion was highest in 2022 were Guadeloupe/Saint-Barthélemy/Saint-Martin (65%), French Guiana (51%), and Île-de-France (50%). Discussion – Nearly half of people born abroad who learned of their HIV-positive status in France were infected after arriving in the country. This proportion varies by mode of transmission, country of origin, and region of residence. These estimates could enable a more tailored approach to HIV prevention and care among people born abroad.