AS Monaco vice-president Vadim Vasilyev has revealed that Real President Florentino Perez is still frustrated at having missed out on the 19-year-old.
Once it became apparent that the teenage forward could be on the move in the summer of 2017, widespread interest followed amongst Europe's elite.
Los Blancos were said to be in pole position to land the Golden Boy of French football, who led Monaco to the Ligue 1 title and the semi-finals of the UEFA Champions League.
Mbappe was, however, to remain in France and link up with PSG on an initial loan, which has since become a €180m permanent transfer.
And Vasilyev reveals that Real are still cursing their luck at failing to get a deal done.
"These two clubs are friends. I have spoken with [Real president] Florentino Perez and every time he sees me he always blames me for not selling him Kylian Mbappe," he told RMC Sport.