The 27-year-old former Chelsea defender and dead-ball specialist made his move public today after passing a medical and agreeing personal terms.
Neither Chelsea nor PSG have formally announced the £50-million deal.
"I'm just concentrating on playing,” Luiz tells Brazilian newspaper Globo Esporte. “I just signed a five-year contract with PSG. But what we plan for today might not be right for tomorrow.
"In the future I will have a child, a family and my priorities might change.
"You have to think of others, not just yourself.
"If a football player could plan his whole career, he would say: 'What I want is to play on this team, be a champion every year, and be selected for the national team.'"