If other teams don't have the same quality of players as PSG, then I believe it will be difficult to break PSG's dominance in the next few seasons. This isn't because they won the Champions League last season, but because the quality of the players they have is far superior compared to other teams currently. PSG's strength is also much stronger now because overall, after winning the Champions League, they will be even more motivated.
The motivation of the PSG players for next season is certainly still quite strong, as they will remain as strong as last season and will strive to strengthen their weaknesses. So, let alone Ligue1 teams competing with PSG, teams from other leagues will likely still struggle to face PSG next season. I also have no confidence that any other team in Ligue1 will overwhelm PSG in their bid to win the title again next season, as the quality of their players and the strength of their squad are more than enough to defeat any other team in Ligue1.