The Catalan giants are also said to be close to securing deals for Ousmane Dembele and Philippe Coutinho.
In Paulinho's case, the Daily Mail reports that a fee worth €40m (£36.5m, $46m) has closed the deal for the midfielder, who has been with Chinese Super League club Guangzhou Evergrande since 2015.
The former Tottenham Hotspur midfielder has been a key player for the club, where in his three seasons with the Chinese side, he has won two league titles and the Asian Champions League on one occasion.
The Brazilian has not hidden his interest in playing for Barcelona and revealed that he was hoping to get a clearance on a deal before the end of the week.
"It is a unique opportunity for me to be able to play for Barcelona, the best team in the world and surrounded by the best players," he had told Mundo Deportivo.
"I have to talk to my president, since I got the proposal I have not stopped thinking about it and I am waiting for everything to be resolved this week," Paulinho added.
The deal will allow the La Liga club to now shift its focus to other targets, with Dembele and Coutinho still in the reckoning.
The Catalan giants have begun negotiations with Borussia Dortmund over Dembele, and it is expected that they will meet the Bundesliga club's €100m valuation. It has also been reported that Barcelona have already agreed terms with the player for a move to the Camp Nou.
The 20-year-old attacker, currently absconding from training according to the German club's manager Peter Bosz, joined Dortmund from Rennes last summer and made 49 appearances across all competitions, scoring 10 goals and assisting 21 in the process. The versatile forward can play either on the left wing – Neymar's position – or through the middle as an attacking midfielder.
Barcelona also hold an interest in Liverpool midfielder Coutinho, and have been given a positive update by Reds manager Jurgen Klopp, who hinted that they may be forced to sell under pressure from the the club's owners following their 3-3 draw in the Premier League against Watford.
ESPN's Spanish channel ESPN Deportes reports that any deal for the midfielder will also be worth more than €100m, including various performance-based bonuses.
"As a manager of a football club, I have bosses that decide, for example – just in general – if we sell a player or we don't sell him. Then I have to accept it," Klopp said, as quoted by the Liverpool Echo.
"If they don't sell him, then I am not involved any more. I'm responsible for all of our players, not just one or two or three, but all of them.
"I can't say anything about it, the only thing is I work with the players I have. That's what I'm always doing," he added.