According to Marca's Juan Ignacio Garcia-Ochoa, the defender is an "attractive proposition" to Los Blancos but "negotiating with the French club isn't an option."
It's said Real won't talk to the Parisians because "conversations with the owners of PSG are reserved, if necessary, to address the signing of Neymar."
Real let defensive mainstay Pepe leave for Besiktas last year, while Sergio Ramos is now 32, so a new centre-back option is needed at the Santiago Bernabeu.
Marquinhos, 24, is one of the best young defenders plying his trade in Europe. He has the technical ability to provide cover in midfield, and his pace is a valuable asset too, which would make him an excellent buy for Los Blancos.
However, if Real have ambitions of signing Neymar, it's understandable they might not want to jeopardise that possibility by pursuing PSG's other stars, which could sour the relationship between the clubs.
Madrid sold Ronaldo to Juventus in the summer, but their only attempt to replace him was to re-sign Mariano Diaz from Lyon.
Their decision not to pursue other options seems to have backfired:
Neymar is one of the few players in football who might be able to replicate Ronaldo's output.
The Brazil international has been shining recently for both club and country:
Real's need for more goals is just as great as their need for defensive reinforcement.
Neymar is not only a prolific scorer, but he's a creative forward with superstar quality, so it's understandable he would be seen as a priority for Los Blancos.
While it may preclude them from pursuing other targets like Marquinhos, foregoing those players in favour of other options would be worthwhile if it helps them secure Neymar in the future.