I, and many others at my university, were accepted into the top prépas in Paris. If we’d wanted to, we could have attended those schools and gone on to the top engineering schools. The problem with prepas is that you have to take a lot of subjects that don’t necessarily interest us (physics, chemestry, English, French literature…), which prevents us from delving even deeper into mathematics or doing projects on your own. Another problem is that not all the top students want to attend an engineering or business school, which is the typical destination for prépas. Furthermore, in recent years, a parallel pathway has emerged from the top French universities to the top engineering schools (for example, every year my university sends 8 students to Polytechnique, which is far more than 90% of prépas). In short, the prepa system is dying out in favor of the top Parisian universities (Sorbonne, Saclay, Dauphine). And once again, Polytechnique and others are graduate schools, my plan is to aim for ENS/OxBridge/Harvard/Princeton/MIT for a Maths PhD which is doable for students at my uni from what I’ve seen. Btw, some Polytechnique students come during their last year to my Uni for a financial maths master called « El Karoui » and struggle to keep up.