The 19-year-old is being talked up as Europe's next big thing after a fine breakthrough season for Marseille in 2016-17, when he made 30 appearances, scoring three goals and claiming seven assists.
The midfielder has been attracting attention from all across the continent but he is already being earmarked as either a future star for Real or Barca with the La Liga rivals both reportedly set to move for the youngster next summer.
Real are thought to have a slight advantage as coach and fellow Frenchman Zinedine Zidane is a hero of the teenager's, but whoever ends up trying to lure him away from the Stade Velodrome will likely have to fork out a significant amount as he's under contract until 2021.
Barcelona's trump card in any future negotiations for Lopez, however, could be that club legend Antoni Zubizarreta is the transfer chief at Marseille and he may push him in the direction of the Nou Camp instead.
Lopez has begun the season well, making eight appearances in all competitions and the France Under-21 international has already managed three assists from the middle of the park.