Who is the most expensive player in PSG?

Can you tell me who holds the title of the most expensive player currently on the roster of Paris Saint-Germain Football Club? Is it one of their star forwards, a midfielder with exceptional skill, or perhaps a defender who has commanded a hefty transfer fee? I'm curious to know which individual player has fetched the highest price tag during their acquisition by PSG, making them the most valuable asset on the team from a financial perspective.