The Brazil international lasted just a year at Barca, having been sold and re-signed by Guangzhou Evergrande between 2017 and 2018.
"If I still think of Barça? If my departure was unexpected? Of course! As much as I can, I watch the games," said Paulinho.
"I would never forget Barcelona because it was a brilliant experience for me.
"In football, you never know how long a stage will last, but we must be ready for any decision."