We investigate applicants’ behavior in a dynamic matching mechanism. In 2018, France moved from a centralized assignment system for university admissions (called APB) to a more decentralized and dynamic assignment system (called Parcoursup). One benefit of a dynamic mechanism is that it allows applicants to change their preferences over time (e.g., due to information acquisition or coordination with peers). We investigate whether this is the case by surveying applicants before the mechanism to elicit their preferenc list, which they would submit to a direct mechanism. We match this survey data with Parcousup data to compare their reported preferences with their revealed choices. After the mechanism, we survey participants again and ask why they may have deviated from their initial preferences. Moreover, we ask for applicants’ strategies, expectations, and satisfaction with the outcome and the procedure. Finally, we investigate whether the dynamic mechanism helps students from lower socioeconomic background to be matched to better universities.