Who the hell is this guy? his name is Mathis Amougou who played in Saint-Etienne. 19 appearances, 0 goals, 0 assists, and almost of his rating is below 7. His market value is just 350K Euros, but Chelsea sign him by spent 15 Million Euros until 2033, which is 8 years contract.
A very poor statistic for 19 years old player, this could be one of worst signing.
While I agree with you, I just wanted to give their perspective on the deal. The fact is that when you are a team like Chelsea, even if the player is worth 350k, you do not offer 500k and get away with it, other teams know that you are loaded with money, so they ask for more.
Like if some relegation level team, or championship team asked for the same player, they could have gotten away with a million or less, but when Chelsea asks, or any other rich club asks, the price is 15 million, because they are rich. I know that sounds unfair, but that's basically a punishment from small clubs to big clubs in exchange of big clubs being rich and always getting something, and small clubs never do. That is why they overpaid that much... I mean probably.