Ligue 1 is competitive, and maybe very competitive if we look to the table starting from the second position. The difference between a team and the teams directly above or under it doesn't exceed 3 points so the ranking might shift with every round technically.
Now when it comes to PSG, it is sure that they are very different from the others, mainly financially. It is basically the only team from years that is able to compete and reach advanced stages in UEFA Champions League, without counting the first place in Ligue 1.
If it does not involve PSG as a champion challenger, it may be true that the second to fifth positions in Ligue 1 are much more competitive, but we want a balanced fight in terms of competing for the title. This is what the teams in Ligue 1 do not have because they are less competitive with PSG as one of the strongest teams. Even to beat PSG's dominance can hardly be achieved by any team currently in Ligue 1 because in terms of the quality of the players they have, they are far below the standard of players owned by PSG.
The only hope for the teams below PSG is fighting to qualify for the Champions League and currently the competition is much more interesting between Marseille, Nice, Lille and Monaco because the four teams have a fairly close points difference to compete to secure a position in the Champions League zone.