The 26-year-old was officially unveiled by the French champions on Tuesday, after the capital club agreed to pay his release clause fee.
Having scored 104 goals in 138 appearances for the Partenopei, De Laurentiis is disappointed by the prolific striker's decision to leave Naples, but has wished him luck in his new challenge.
"Dear Edy, today is the day that I would never have wanted to arrive," he wrote in an open letter on the club's official website.
"Today, you have chosen a big city and an emerging club. My dear friend, I hope for your sake that you have made the right choice," he added.
De Laurentiis also revealed that he had hoped Cavani would change his mind up until the last minute.