Since 2017, geriatric medicine has been available as a postgraduate specialty to French year 7 medical students. We investigated the incentives of the 171 French medical students who opted for geriatric medicine as a postgraduate specialty subsequent to year 6 national qualifying examinations in 2017. A prospective quantitative survey-based study was conducted by means of a questionnaire compiled online and sent by email between December 2017 and May 2018. The questionnaire comprised 43 questions, including 14 single or multiple choice questions, 28 scaled questions evaluating factors of influence using a 5-point Likert scale, and one open-ended contingency question. Of the 171 students, 139 responses were received. The national response rate to this questionnaire was 81.2%. One hundred fourteen students (82.6%) had previous experience of training in geriatric medicine, which for 95 (84.0%) students took place between years 3 and 6 of medical training. This training influenced the choice of 102 respondents (90.2%). Factors reported as having exerted a strong or very strong influence were in particular the rewards of working with older adults; positive personal encounters with older adults in the past; the appeal of interprofessional teamwork; the challenge of cases involving complex diagnostic and therapeutic decisions; the challenge of patients with chronic conditions. The present study is the first to focus on the reasons why French students choose to specialise in geriatric medicine. The results emphasise the importance of training programs in geriatric medicine to promote enthusiasm for this specialty.