The fee, which could potentially rise to £50m, was agreed on Friday evening - with the Brazilian defender set for a medical later today.
Luiz's move is widely expected to be completed by the end of the day, and the 27-year-old has reserved special praise for the west London side.
"Thank you Chelsea for three years and a half of a great partnership. I gained friends, matches and titles that will always live on in my memory," he told 'Globo Esporte.'
"I thank the staff, players and fans! Geezers! This story wouldn't have been possible without you.
"I am sad to leave because of the friends that will stay but I am happy to be on my way to another big European club and to go to a city that has always fascinated me.
"This is a new stage and new challenges and I am sure that together we will go even further. Allez Paris!"
The former Benfica defender is currently in Brazil preparing for this summer's World Cup, where he is widely expected to partner PSG captain Thiago Silva in central defence.
Luiz, who made 143 appearances for the Blues, took to social media on Saturday morning to send another thankful message to Chelsea.
He said on Twitter: "Tks CFC for this time of great partnership. I'm thankful for all! It's a new challenge and together we'll go even further. Allez Paris!
The Brazil international also sent a message of thanks via Facebook, where he revealed: "Thanks Chelsea for the three and half years of great partnership.
"I've made good friends, won many titles and those memories will last with me for ever. I'd like to thank my team-mates, all staff and all supporters (my geezers).
"I'm leaving with great sadness but at the same time excited for the new challenge that lies ahead in this great club in a city that has always enchanted me."