But others have less scruples, especially when it comes to rentals between individuals.
In total, 26% of Parisian rents remained in excess in 2020 despite the law reintroduced in 2019, underlined the Observatory of rents of the Parisian agglomeration (Olap) in a note published in mid-December.
The principle of rent control was introduced in several large cities in France to fight against abuses which made the search for housing very difficult for the most constrained budgets. The measure imposes a ceiling on owners which varies from district to district, and applies where "there is a marked imbalance between the supply of and the demand for housing".
For Yves, owner of three apartments with capped rents in the capital, this law "was absolutely necessary. The housing situation in Paris is lamentable".
But it did not really facilitate the search for a Parisian apartment for Marguerite, 26 years old and on a permanent contract. "There are still many owners who do not respect the law," she sighs between two visits.
"Today, the trend in some ads is even to no longer indicate the price. Landlords complained of receiving comments on the high amounts of the proposed rents," she said to AFP.
Some people give up on renting altogether, like this owner whose property has been empty for four months and who told AFP he would rather keep it vacant than reduce his rent by 30%.
Others admit to making do with the law.
"How to get around the rent control?" : a simple search on the internet provides a lot of advice on how to get off the rails. An owner explains having thus found a trick, he specifies renting a "company accommodation or secondary residence", in his advertisement on a site of individuals to individuals, a mention which allows his property in the south-west of Paris to escape the capping.
Since 2019, 10 fines in Ile-de-France
Many real estate agencies ensure to block the smart ones.
At La Forêt, rue d'Auteuil in Paris, an advisor explains: "We expose the risks incurred to those who are above the reference rents. Either they fall, or they persist. When this is the case, this must be justified by a rare service such as a balcony or a garden ", otherwise the agency refuses the file. In the end, she estimates that around 5% of assets under management "are a little more expensive than they should be".
Has the law succeeded in lowering prices where they were too high?
According to real estate professionals, it allows a "certain regulation of the market". In its note, Olap also points to a "moderating effect (...) undeniable, although moderate".
But on the side of sanctions, the results are not necessarily conclusive: they are rarely applied, regret several real estate agents questioned by AFP.
Since 2019, 10 administrative fines have been drawn up by the prefecture of Ile-de-France, seized of 98 files, indicated mid-December Mickaël Nogal, co-rapporteur of the decentralization bill known as "3DS".
The deputies gave the local communities the possibility of sanctioning themselves the lessors who ignore the framework of the rents, a provision which demanded in particular the elected Parisians.
For Marguerite, who has been living in Paris for several years, it is a discovery.
"I have never heard of sanctions, including when you are already in the accommodation," said the young woman, who regrets the lack of communication on this subject.
According to Bertrand Pallatin, "between those who are not even aware of the measure and those who have struggled to find accommodation, it is very rare for a tenant to undertake a procedure".
Provided for by the Elan law of 2018, the ceiling on rents only concerned Paris and Lille until June 1, 2021. On that date, it was extended to nine towns in Seine-Saint-Denis, north of Paris, grouped together in the public establishment Plaine Commune. Since November 1, Lyon has joined the system, and Bordeaux and Montpellier must do the same in 2022.