The match between Lorient and Brest also ended just now. Right now Lorient is in the second position ahead of Marseille. Lorient is ahead by 2 points, and right now it feels like even though PSG is supposed to be the winner of this League, they are going to have some good competition this season at least. But I believe that PSG is not going to be bothered too much about the competition that are currently chasing them.
I don't think so because Marseille's main goal is to have a successful season in the Ligue 1 already. Maybe you will ask "Why did they lose a very easy game then?". I think that the answer is "The players had some fatigue after their Champions League game.". They played here only after three days in the end. Despite demolishing Sporting by 4-1 there they must have still been tired before starting this game.
But of course getting this loss right before their PSG fixture in the league is very bad for Marseille. As that game is in Parc des Princes as well, PSG have a big opportunity to make the gap with them bigger.