In Geneva, Switzerland, students in secondary 1 education are grouped into different tracks according to their academic level. The tracking system in Geneva has been reformed recently. Prior to the reform, the tracks were very hierarchical but less selective; following the reform, the tracks are still very hierarchical but the entry criteria are more selective and there is greater flexibility to move from one track to another. Using longitudinal data, this article compares these two types of tracking system and analyses the inequalities produced in terms of the skills acquired by students and the path taken once compulsory education is completed. Our analysis shows that the new tracking system following the reform has a major impact on students of medium ability. They are more likely being assigned to a lower track, which has a significant adverse impact on their learning and subsequent pathway through education.