Speaking after the move which will see him reunited with a former teammate and Monaco coach, the 2010 World Cup winner said it was “tricky” leaving England.
“It was tricky for me to leave after 13 years in England,” the former Barcelona man said on Wednesday.
“I started my career there, won a lot of trophies, played for two top clubs, and made more than 500 appearances. I sometimes even feel more English than Spanish.”
He joined the Stade Louis II outfit on a three-and-a-half-year deal valued at $11.5m.
On why he left Chelsea, he said: “Three months ago I wasn’t thinking about leaving Chelsea, but the circumstances helped.
“I was getting less game time. At first, it was a surprise for me, but I came to the decision with my family.
“It is the best thing for my future. I feel like a young player again and can’t wait to get playing.”