Seri remained at Nice, making a total of 43 appearances across all competitions last term - scoring twice and recording 10 assists.
He now looks set to leave the French club, however, and his agent Franklin Mala claimed Napoli is the ideal destination for the 26-year-old, who has been linked with a move to Chelsea, but insisted last season's Serie A runners-up must act swiftly.
"We hope to have positive news from Naples in the next few hours," Mala told CalcioNapoli24 on Thursday.
"There's been informal contact with Napoli, but still no step forward. We're ready to meet Napoli.
"Napoli are in pole position, Seri prefers Naples to anywhere else. Napoli need to speed up in every way to close the deal.
"His €40 million (£35m/$47m) release clause expires on July 15, so they have to pay it by that date. After July 15, Nice can ask for any amount.
"There are two Premier League teams in for Seri but I can't say anything else."