Nzonzi has moved for €26.65m plus €4m in bonuses.
“I realised Roma wanted to buy me and that alone was very pleasing, because this is a great club. I always want to learn and improve, that is the most important thing for me.
“Age doesn't matter, but rather your desire to work hard and always give your best. I hope to bring some of my experience to the team.
“Director Monchi brought me to Sevilla and he helped me a great deal, so there is reciprocal respect. I am happy to be working with him again.
“The objective is to win trophies. We work hard and will do our best to achieve that. I thank the fans for welcoming me at the airport and promise to give my all. I hope to become important for Roma."