Luiz signed for a staggering £50 million for PSG ahead of the World Cup, leaving them unable to splash out an even higher amount on Angel di Maria.
The French champions were strongly linked to the Argentine, who signed with Manchester United for £60 million in August.
Luiz told French television channel TF1 this week, of his former Benfica teammate:
"I have great memories with Di Maria. When we were at Benfica were like fingers of the same hand. I was always at his house and he at my house."
Various reports had tipped PSG as favourites for Di Maria, but it really was their concerns over financial fair play which led to them being unwilling to match United's offer.
Perhaps if they had not gone in for Luiz, they could have signed him instead - or had they not paid Chelsea such a ridiculous amount, there could have been a possibility to sign both.