Introduction: According to French guidelines, migrants are often not fully vaccinated. The objective of this study is to assess the practices of physicians practicing in France regarding catch-up vaccination for migrants. Methods: Through several professional medical societies, a survey on infectious disease prevention practices was conducted via a self-administered questionnaire in 2016–2018 among physicians practicing in France who are involved in the care of newly arrived migrants, regardless of their specialty. Results: A total of 372 physicians responded to the survey. Respondents had a median age of 42 years; 64.5% were women, and 43.8% practiced in the Île-de-France region. In the absence of information on a migrant’s vaccination status, physicians’ practices regarding catch-up vaccination appear highly varied: administration of the full primary vaccination series (33.1%), use of pre- (32.8%) or post-vaccination serology (16.9%), resuming the vaccination schedule based on age while assuming the individual was properly vaccinated with the primary series (26.6%), or gathering information on vaccination practices in patients’ countries of origin (23.4%). Female and male physicians employ different vaccination practices, with the former more readily utilizing specialized websites or post-vaccination serology tests, while the latter more often administer a complete primary vaccination series. The majority (55.4%) of respondents do not administer more than two vaccine doses on the same day. Conclusion: The practices of physicians practicing in France regarding catch-up vaccination for migrants are heterogeneous. The ongoing development of recommendations led by the HAS and the SPILF should help standardize these practices.