I agree that Real Sociedad is a strong team, in fact, if they were not strong enough they could not stand in a tournament like the Champions League, and playing in this tournament for any team means they are strong enough to make a problem for other teams but I think playing against a team like PSG with all the superstar players they have can't be easy for a team like Real Sociedad and let's say I think PSG will easy pass this stage in the Champions League against Real Sociedad considering the situation they have.
PSG was indeed able to pass the last 16 stage to advance to the next round even though the second leg match was at home to Real Sociedad. However, what needs to be seen here is that the level of difficulty for PSG must be there to get through all of this because there is no easy way in the Champions League to get through round after round. I think Real Sociedad will continue to show their skills in the second leg when they host PSG even though Real Sociedad was two goals behind in the first leg.