PSG can claim the French Ligue title much early before the season comes to an end. I doubt there is any team team that can stop them from winning the French Ligue title. Both Marseille and Monaco has been in form form this season but I don't think they can compete with PSG for the title.
That's what makes this league not so interesting because PSG can claim the title much earlier before the season ends so the league competition is not so competitive. It is difficult for any team to break PSG's dominance and that is not at all the competition that football lovers expect. To be a competitor for PSG in the fight for the title, it takes a balanced player strength and that is not possessed by Marseille or Monaco so it is difficult for both of them to compete with PSG.
If you look at the Marseille team when facing their opponents they are able to win the match with a fairly large score but when they want to compete for the title with PSG they actually lose their chances, both Marseille and Monaco are both seven points behind PSG so it is difficult to catch up on the points.