Typically, you have two agents. One representing the buyer and one the seller. The property owner pays the agent fees and the two agents split it. Regardless, the entire amount is paid by the property owner. Only difference here is that Juve aren't represented by an agent so the fee they pay isn't split between their agent and the player's.
If it was a real estate deal and the property owner wasn't represented by an agent, he/she would negotiate with the buyer's agent to reduce the fee since that agent didn't have to share it. So if the typical two-agent deal involved a 6% fee, you'd cut it to 3%.