"But it was a very, very hard decision. I waited two years to take this decision but now I'm very happy I have because it is a great club."
The 16 year-old Frenchman added: "Arsene Wenger played a big part in me coming here," said Sunu. "He is French of course and it is easier for me to take his advice.
"I would like to play for his first team if it's possible. It's my dream, so that has to be my target."