The Gunners completed a £27million move for the 18-year-old French defender last summer but then loaned him back to Saint-Etienne for the current campaign.
"He improves every game and I think he is a great player. He's strong with good technique. He's quick.
"I think he has a lot of quality to play at Arsenal."
"The future look bright for them and I hope they continue in the same way.
"He's strong and hopefully he will adapt himself really quickly. In a club like Arsenal with French players I think he can do really well."