I think the red card was fair enough and the referee was right about the red card but Lens aren't lucky because they had to play with players less than PSG for more than 80 minutes, this can be even harder if you consider they are playing against a team with many superstar players like Messi and Mbappe, but if they were playing with the full team maybe they had a good chance to even beat PSG.
I agree that red card was the right decision. The logic of red card is to punish someone who attacked directly at the player with a possibility of injury as well, and that dude put the bottom of his shoes right on Hakimis ankle, that should be as hard as it gets and it's a direct red card without a doubt.
However, I also think that even without that red card, I would have seen that as a game that PSG would have won, they could have played 11vs11 all game and PSG would have still won that game, they were just too much better. Lens in trouble now, they need to win all they can from this point on to get 2nd place at the end of the season. PSG just made sure nobody can get close, the league is over for them basically.