This is the natural result of putting price caps on a market. It says so in the article. Only increasing supply can help with the cost of housing and it needs to be done above demand levels. Until units start sitting vacant that are actually on the market, you won't see prices go down or people's needs actually met.
Tokyo is the most populous city on the planet with like 3x the population of Paris, and yet it's remarkably affordable. Why? It's easy af to build there. Japan has a simple, nationwide zoning code that makes it extremely easy and streamlined to build new housing.
Clearly Tokyo has found the room. Paris has plenty of room.
Yeah, rent control is basically universally agreed-upon by economists to be a disaster for a city in the long term. If you want affordable housing, you need abundant housing.
Imagine 2 scenarios and imagine which one has cheaper rent:
There are 9 homes for every 10 households, or
There are 10 homes for every 9 households
It's not hard to imagine. If landlords have a credible threat of vacancy, that gives the rest of us negotiating power. And negotiating power is power.
The problem is, tenants need a place to stay, while landlords don't need to provide it. They want to, but they can (mostly) afford to let an apartment sit unrented, especially if they raise the price for the surrounding units. Someone will eventually pay the price.
In a "free" market, those with the capital have power, those that don't... don't.
The best solution is for the state to build public quality housing that is well located, and charge rent only based on “cost”.
Vienna did this when they had a socialist government (in the early 20th century lmao), and still to this day since there is so much public housing and the cost to rent is so low, it controls the wider cost. Even non-public housing there is much cheaper than pretty much all cities of its size.
Also, creating laws that desincentivise owning more than 1-2 properties (taxing the shit out of third homes for example, and more for each additional one), or just making it outright illegal.
Letting the market decide the rent will not magically create more housing, only make the existing housing in a high-demand place like Paris very expensive. The effect might be that it is easier to find an apartment, but only because you have forced the poor out of the city and moved the housing crisis further away from the city. Of course the landlords would be happy if they could charge some 3000€ per month for a small studio apartment in a dodgy neighbourhood, so of course the economists say this is a good idea, since line go up is good.