On the other hand, the fact there were so many different universities in Paris in the late 20th century was also pretty artificial: De Gaulle got sick of all th

On the other hand, the fact there were so many different universities in Paris in the late 20th century was also pretty artificial: De Gaulle got sick of all these spicy students having opinions and split the whole thing up. But it's all just rather arbitrary rankings of rather arbitrary social constructions anyway, and as you say it's not that helpful for making accurate decisions for where you should apply anyway as what really matters is your supervisor and the support from the administration.