Speaking to Sambaslots, Petit said: "Declan Rice proved last season that he is worth £100 million and now he has taken that to the next level.
"He proved he was a leader in the team last year, acting like a captain, every game he has been at his highest level. He looked tired after the Euros and picked up a silly red card, but he has step by step progressed to the very highest level.
"He is worth £100 million without a doubt and it would be very, very expensive if a club tried to sign him from Arsenal.
"Alongside Nicolo Barella at Inter, I would say that Rice is the best midfielder in the world at the moment. In Barella, there is a player that I’m not surprised has been linked to Real Madrid."