The 25-year-old Brazil forward, Neymar has set a new record for the highest signing fee of 222m euros (£200m) from Barcelona. He smashed the previous record set when Paul Pogba returned to Manchester United from Juventus for £89m in August 2016.
Neymar said he has joined “one of the most ambitious clubs in Europe”.
“Paris St-Germain’s ambition attracted me to the club, along with the passion and the energy this brings,” he added.
“I feel ready to take the challenge. From today, I will do everything I can to help my new team-mates.”
Neymar will earn 45m euros (£40.7m) a year. 865,000 euros (£782,000) a week before tax from the initial five-year deal, a total outlay of £400m.