Actually I don't think it's harder to get into than Harvard. They have many, many applicants because they don't put any restriction. You can apply even if you didn't go to high school.

Also, they have no tuition but neither do the public universities in France ("Grandes Écoles"), and the most selective and prestigious schools are public. So while the "no tuition" thing is impressive for a private school and may sound like a dream for Americans, it's not really rare in France considering the choice you have with public schools.

Finally, not really related to the way they teach there, but here's the director (same guy in the picture on the article) spanking a girl in a classroom during off-hours (nsfw). http://www.19h59.com/WTF/10238_Le-directeur-de-lecole-42-don...