Native French here, I had never heard of that word.

Given these conditions are illegal, such offers are rare on mainstream platforms (and should be reported). I highly doubt the only choices are 500€/7m2 or the street.

No one is forcing you to buy drugs, kill someone or accept an illegal contract.

Don’t know where those numbers come from, it is illegal in France to rent something that is less than 9m2.

You know what gives artists money? Buying their music instead of renting it through a middleman.