PSG will continue to dominate the French ligue 1 if rich investors don't invests in at least five French Legue 1 clubs so that they can buy quality players they can use to build up formidable teams that can rival PSG and make the French ligue 1 title difficult for PSG to win. Clubs have expenses to cover, so I think the money each club earns at the end of a season isn't enough to buy them quality players and buy up a team that could win the French ligue 1 title.
They are making the league become very boring to watch because before the stary of the season you already know that PSG will become champions due to low competition in the league, other teams need to wake up and their owners should invest money in the teams so that they can have a team that will make the league become interesting to watch again. PSG don't have much expensive players because no notable star is there so this is the opportunity for the owners of Monaco, Marseille and Lille should invest so that the other teams can have the chance of winning the league ahead of PSG.
Other clubs in the French ligue 1 need to do something about improving their performance so that the French ligue 1 will become more competitive, which will attract more people into watching French ligue 1 matches. It's not that Marseille, Monaco, and Lille don't want to invest in their squad so that they can have a chance of winning the French ligue 1 title, but they lack enough resources to overhaul their teams to the level where they can win the league title ahead of PSG.