Actually PSG failed to win the match despite playing extremely well. The reason for this may be that the team has too many star players or there was something wrong in the management of the coach of the team. Which gets the players in big trouble.
I also don't understand why PSG can lose at home to a mid-table team like Lyon, even though PSG have the best players and even in the first half Lyon had one chance to score a goal through a penalty which was saved by the PSG keeper. But in the second half Lyon again made the lead by scoring one goal and that result was able to bring Lyon to victory even though this result would not affect PSG's position in the Ligue 1 standings.
But I think I know why they lost this game, actually, PSG lost the game against Lyon and they could lose this game even if they were playing against another team because the whole team is not in a good situation at all. They are going to lose Messi at the end of this season and Neymar lost the whole this season because he is still injured in the other hand there is some news about PSG changing the coach soon which can surely have a negative effect on this team.
I'm curious, where will Messi go at the end of this season because according to the information I got earlier, that Messi got a new contract at PSG. So, maybe the information is still unclear because with PSG's performance like this, then of course PSG must make an overhaul in their squad and management.
However, I believe that the number of star players in a team's squad, I believe this will not make the team's performance worse. Because in my view the factors that make their performance poor are the management factors that are not good enough so that the results obtained are also not optimal.