PSG had a really poor game and they were nearly losing as well. Mbappe and Barcola were really ineffective in the attacking line. Goncalo Ramos was the right move for the team as he scored the equalizer in the stoppage time. But is this 1-1 result a problem for PSG? Of course not. Because the gap Brest is still 9 points and I don't expect any team to get too close to PSG from now on.
Mbappe would get another Ligue 1 title before leaving but I wouldn't expect him to be champion in the Champions League this season. PSG aren't that good now. They can't eliminate Manchester City and Real Madrid with their current performance level.