The Brazilian admits that he is worried about his first-team opportunities following his compatriot's arrival, revealing he will sit down with the club to discuss his future
The Ligue 1 champions have agreed a fee believed to be around €49.5 million with the Premier League side for the 27-year-old, a world-record sum for a defender.
The move has been welcomed by Marquinhos but the youngster is also concerned the signing could limit his playing time, with Barca rumoured to be interested his services.
"If Barca is interested in me, obviously, that's something nice!" he told le Parisien.
"It's flattering because Barcelona is a club that has won all the tournaments in the world. Other than that, I cannot say anything else about Barca.
"I have a contract that goes until June 2018. Now, we'll see. I do not know. Anyway, I will talk with the club and my agent about my future because this will be a very important season for me."
The former Roma defender, who arrived in Paris last July from the Serie A outfit for €31.4 million, did, however, congratulate Luiz on his decision to join the club.
"I have to say that David is a friend," he added.
"He's a great lad and a great player. Besides, I think he made the right choice by committing to PSG. But when you see players like David Luiz arrive, it will be even harder for me."