I assume because of the rampant crime. I had to leave my bag in a room full of bags behind the desk.

There were no cameras in there, so thieves could theoretically go through anyone's bags, but at least the hostel wouldn't have their bargain bin shit stolen? Idk to be honest, Paris was comically bad from beginning to end.

I still don't understand how a major tourist city like Paris can have a subway system that is entirely and exclusively in French. I had just come from Seoul and Tokyo and couldn't fathom how Paris's transport system was.