Napoli coach Rudi Garcia has welcomed the arrival of Natan.
The young defender is joining Napoli from Red Bull Bragantino as a replacement for Bayern Munich signing Kim Min-jae.
Garcia said: "He is a young Brazilian defender who moved to Red Bull Bragantino. We know what these Red Bull teams are like. I faced Leipzig and Salzburg with Marseille in the Europa League, we beat them and went to the final against Atletico Madrid.
"I know this football well, it's made up of young people who run a lot and press a lot. Natan is also a player who presses a lot, who isn't afraid to play high and leave half the pitch behind him.
"He's powerful, but let's give him time to learn the language and teammates, to work in training to give him some advice on how to play and on what we have to do."