The initial draw had put PSG against Manchester United while Real looked to be facing Portuguese side Benfica.
However, a “material error” forced UEFA to cancel the pairings and restage the draw.
The error involved United who finished top of their group and were originally drawn to face Villarreal in the Round of 16, which should not have been possible as Villarreal qualified from the same group as the English club.
The Red Devils were then seemingly omitted from the teams which were drawn to face Atletico Madrid, despite being one of the teams eligible to face the Spanish champions.
They were eventually drawn against French giants, Paris Saint-Germain, in arguably the toughest tie of the round.
After a complaint by Atletico Madrid, UEFA was forced to reschedule the draw.
See final draw below: