It is very possible indeed and we look at it realistically and the overall strength of the two teams and it is clear that PSG is slightly stronger than Real Sociedad so if there are no surprises then PSG will be able to get through this round of 16 without any significant difficulties.
Real Sociedad is a surprise team so far, I see that Real Sociedad does not have excessive strength and it has been proven now that their performance in the last few matches has declined in their domestic league matches and this is quite profitable for PSG.
Real Sociedad might be a team that lack of strength, but that's fine since they have a good defensive too. At least they have a chance to beat PSG even though it looks competitive, unlike most of people who think PSG will obviously win the match.
Based on history, PSG's performance was really poor during knockout stage, they only very strong during group stage.