Article dans une revue: Using comprehensive administrative data on France's single largest financial aid program, this paper provides new evidence on the impact of large-scale need-based grant programs on the college enrollment decisions, persistence, and graduation rates of low-income students. We exploit sharp discontinuities in the grant eligibility formula to identify the impact of aid on student outcomes at different levels of study. We find that the provision of 1,500 euros cash allowances to prospective undergraduate or graduate students increases their college enrollment rates by 5 to 7 percent. Moreover, we show that need-based grants have positive effects on student persistence and degree completion.