Barton insists the Chelsea midfielder is being over-hyped by the English press.
He told JDD: "In England there are boxes and it is impossible to get out of them. At this moment, for example, one only swears by N'Golo Kante. It's the fashion. For agents, it is the best environment in the world.
"Oh! He is very good, but I played against him three weeks ago and he is not. He is a phenomenal tackler who plays in a phenomenal team, not a creator. And then it's impossible to be so definitive with a player who has not played a Champions League game.
"Two years ago, nobody knew him and I was surprised that all the scouts had missed him before. I am skeptical."