"Épater la bourgeoisie" is a French phrase that means "to shock the middle class."
Imagine you are playing with your toys and your mom walks in and sees that you've built a tall tower out of them. She might be impressed, but it's not really that shocking or surprising to her.
Now imagine you take all your toys and make a big mess on purpose, throwing them everywhere and jumping on top of them. This would be much more surprising and might even shock your mom a bit.
"Épater la bourgeoisie" is like the second scenario. It means doing something unexpected or outrageous to shock people who are considered part of the middle or upper class. This could include things like wearing crazy clothing, listening to loud music, or doing things that are seen as inappropriate or scandalous. It's a way of rebelling against the norms of society and showing that you are different and not afraid to be yourself.