Yanga-Mbiwa joined Roma on a season long-loan from Newcastle on transfer deadline day, with the Italian club having an option to make his stay permanent next summer.
The 25-year-old, who made 46 appearances for Newcastle after joining the Magpies in January 2013 from Montpellier, was unveiled to the local media on Thursday.
"I am delighted to be here and I hope to bring something extra to this team," Yanga-Mbiwa said in a press conference. "Things didn't work out in England for me.
"Perhaps because in England they see things in a different away, everything there is based on physicality.
"However, here it's more about ball possession and I believe that the Serie A is more similar to the Ligue 1.
"I believe I can give my best to prove that in England things simply went badly."
Yanga-Mbiwa was strongly linked with a return to France but admitted the opportunity to work under Roma's French coach Rudi Garcia was too good to turn down.
"Garcia knows me and I know him because he used to coach in France," he said. "He was one of the best coaches in Ligue 1.
"He convinced me to come here because he wants to win the league title and I am hungry to win trophies.
"We have a superb squad and we will do all that we can to achieve our aims.
"I know that we have to work a lot and I must give my all."
Yanga-Mbiwa hopes his new adventure at Roma will turn out well for him as he is eager to return to the national team.
The Bangui-born player last featured for Les Bleus in 2012.
"I know that if I play regularly at Roma I will have a chance to play for the national team," he said.
"Right now my focus is on being in top condition for the next game."
Yanga-Mbiwa, who has chosen the number two jersey at Roma, is expected to make his Serie A debut at Empoli on September 13.
Roma finished runners-up to Juventus in Serie A last season and will compete in the Champions League this term.