"I wanted something bigger, a bigger challenge," he said. "My heart wanted a new ambition, that’s why I’m here in front of you. This is what my heart told me to do. I listen to my heart every day. And my heart told me to go to PSG."
There had been speculation that he was disgruntled at Barcelona for not being the sole star, though that is something he has denied.
"No, it didn’t impact my decision at all," he said. "I wanted to come to Paris, and this was only linked to me willing to find a new challenge. It’s not because I didn’t feel like I was the big star – I felt really good there. That’s not what I'm here for in Paris. I’m here for a new challenge and new trophies. I want to dream bigger, to do my best and to do even better."
"We had all the right ingredients for me to sign. I want to be really happy at the club.
"I'm really looking forward to starting to train with my new team-mates."
Leaving Barcelona was a wretch for the forward.
"It was the most difficult decision of my life," he said. "I was well adapted to Barcelona, where there are fantastic players. I've left many friends there. I had to think and re-think about what I want to achieve in my life.
"Things happen very quickly in football. I'd like to thank the players but I felt it was the moment to go.
"I spoke to the Brazilians here and I already feel at home."
Having a sizeable contingent of players, including Dani Alves, Thiago Silva and Marquinhos, from Brazil was not, however, a decisive factor for the player.
"To be really honest, it wouldn't have changed my approach at all if Brazilians weren't here. This wasn't an easy decision, as I've said. I wanted to think about what I wanted to do with my life," he said.
"A lot of people wanted me to talk about it but it's very complicated when you're not sure about something. I wasn't 100 per cent sure about what I wanted to do. It was impossible for me to answer.
"But as soon as I made the decision, I started communicating. I'm very happy. I always ask my heart and it told me to go to PSG."
Asked if he might play against Amiens on Saturday, he replied: "Yes I am ready. If I can play tomorrow, yes, why not?"