Beckham, 37, also revealed he had to turn down offers from England because he could not bear to face Manchester United.
He has signed a five-month contract and confirmed the presence of Carlo Ancelotti and Leonardo, the head coach and sporting director, had persuaded him to join the wealthy French giants.
Beckham knows both men from time he spent on loan at AC Milan.
"I'm very lucky. I'm 37 years old and I got a lot of offers, more now than I've probably had in my career. I'm very honoured by that," Beckham said at a press conference.
"I chose Paris because I can see what the club are trying to do. I can see who the club are trying to bring in.
"It's an exciting city and now there's a club that's going to have a lot of success over the next 10, 20, 30 years.
"I'm very honoured I've been picked to be part of the future of PSG.
"Every club I've played for throughout the world I've been successful with.
"I was successful with Manchester United and always said I'd never want to play for another English club.
"I had a lot of history with Manchester United. It's the team I support and the team I dreamt of playing for.
"I'm very honoured by the offers I had from other Premier League clubs but I didn't want to play there unless it was for Manchester United."
It emerged on deadline day morning that the former Manchester United, Real Madrid, AC Milan and LA Galaxy midfielder, who won 115 caps for England and captained his country, was travelling to the French capital for a medical.
Beckham revealed the deal had been agreed in the early hours.
He also explained his charitable gesture, saying: "I won't receive any salary.
"My salary will go to a local children's charity in Paris.
"It's something exciting and something I'm not sure has been done before."
Beckham said he had not identified a suitable charity yet, and could not announce how much they would receive, except to say it would be a "huge sum".
"It's something the guys will decide, but it's a very good figure," Beckham said.
"That's one thing we're very excited about, to be able to give a huge sum to a children's charity in Paris, it's very special."