The striker ruptured a tendon in his left knee in the Serie A fixture with Livorno and if the surgery goes to plan the Brazilian then faces up to nine months on the sidelines.
However, Rossoneri president Silvio Berlusconi has refused to call time on the star and said: "At 31-years-old he is still young and I think that he can return in a number of months to being the champion of old.
"I spoke to him on the telephone and I told him to believe in himself as he has such a great physical capability."
The former World Player of the Title arrived in the French capital at 9am local time and club doctor Jean Pierre Meeserman revealed that Gerard Saillant, the professor who oversaw the same procedure on the player back in 2000, will once again supervise.
He said: "It was Ronaldo himself who asked to be operated on in Paris by the team that put his right knee straight eight years ago."