The French midfielder has joined Roma on-loan from RB Salzburg.
Gourna-Douath said: "I know how great this club is, so I'm not surprised by my teammates, the city and the training center. Here it's the best, it's an environment where you can't have excuses because there really is everything: the pitch, the facilities, the changing rooms, the staff. Here there is everything we need to win.
"I chose to come here because two years ago I played against Roma and the first 20 minutes of the return match at the Olimpico were the worst of my footballing life because of the stadium and the fans, who were cheering and supporting the team. I was really surprised.
"When my agent called me to tell me that (coach Claudio) Ranieri wanted to speak to me, I immediately said yes. I would like to thank Roma, the Friedkins and (sporting director Florent) Ghisolfi for this opportunity. I am really happy to be here. I can't wait to play in front of the fans. I hope they support me like they did with their team when I played against them."