Grandes écoles are uniquely French and don't, to the best of my knowledge, exist anywhere else in the world. They're vaguely parallel to university level education but the typical course lasts 3 years and is vocation-centric. They tend to focus on specialised subject areas and are generally well known for their high quality of teaching and research.

Traditionally, before you could enter a grande école you had to pass the concours commun. This envolves two years of gruelling study at an école préparatoire which wipes out a student's life for the duration. The effect of then releasing them back into society is that they spend a lot of their time partying and drinking too much.