Regulation :

The seller's obligations:

Sellers are legally bound by two warranty obligations:

-A legal guarantee of conformity

"The seller (professional) is required to deliver goods that conform to the contract and is liable for any defects in conformity existing at the time of delivery.
He is also liable for defects in conformity resulting from the packaging, assembly instructions or installation when the latter was his responsibility under the contract or was carried out under his supervision." ( Articles L. 217-1 et seq. of the Consumer Code ).

-A legal guarantee against hidden defects

"The seller (private individual or professional) is bound by the warranty against hidden defects in the thing sold which make it unfit for the use for which it is intended, or which diminish this use to such an extent that the buyer would not have acquired it, or would have given only a lower price, if he had known of them" ( articles 1641 et seq. of the civil code ).

In addition to these two legal guarantees, there is an optional guarantee that the seller, and even the manufacturer, is free to provide or not provide. This guarantee takes on different names depending on the situation: commercial guarantee, contractual guarantee, conventional guarantee provided by the seller; manufacturer's guarantee provided by the product's manufacturer. Unlike the previous two, this guarantee is not mandatory. Depending on the situation, it may be free, provided by the seller as a selling point, or it may be subject to a fee. The commercial guarantee "…is understood to mean any contractual commitment by a professional towards the consumer for the purpose of refunding the purchase price, replacing or repairing the goods, in addition to their legal obligations aimed at guaranteeing the conformity of the goods…" ( Article L. 217-15 of the French Consumer Code ).

For more information on its various guarantees:
https://www.inc-conso.fr/content/garanties-du-vendeur-tout-savoir-avant-dacheter

The installer's guarantees:

If you encounter problems after having work done in your bathroom by a tradesperson, whether it's a new or existing bathroom, you need to verify several things: that the tradesperson is still registered with the trade register, that they have valid insurance for the current year, and that the insurance certificate covers plumbing, sanitary ware, and electrical work, as bathroom renovations involve all these elements. When you completely renovate a bathroom, you're working on various aspects such as plumbing, electricity, plastering, painting, etc. It's important to have these guarantees.

When you hire a large company, it is important not only to ask for the ten-year and two-year guarantees, but also and especially to request a certificate of up-to-date URSSAF contributions which will prove that the craftsman is in compliance with his social security contributions to avoid any problems for you.

Therefore, these certificates will allow you, in case of a problem, to open a dispute and get a refund.

There are 3 guarantees that you absolutely must check:
-Guarantee of perfect completion (which can be invoked within one year from the date of acceptance of the work).
-Two-year warranty
-Ten-year warranty ( Article 1792-2 of the Civil Code ) For more information on these warranties:
https://www.service-public.fr/particuliers/vosdroits/F2958

The regulations:

For information on regulations concerning electrical installations in residential buildings:
https://www.legifrance.gouv.fr/loda/id/JORFTEXT000032975211/

Defamation:

“Defamation is an allegation or imputation of a fact that harms a person's honor and reputation. Defamation can be racist, sexist, or homophobic. It falls under a specific procedure designed to protect freedom of expression.”
There are two types of defamation: public defamation and private defamation.

Public defamation is defamation that is read or heard by everyone. Private or non-public defamation, on the other hand, is defamation that is stated in private and is not heard or read by third parties.

Defamation is reprehensible whether it is against a person or against a company or its products because it can affect the company's image.

For more information on defamation and its penalties:
https://www.service-public.fr/particuliers/vosdroits/F32079

DTU

There are two methods of laying tiles: sealed installation and glued installation.

These installations are governed by implementation rules explained in the DTU (Unified Technical Document).
Each contractor assumes ten-year liability for damages affecting the structural integrity of the building's equipment. (See Article 1792-2 of the Civil Code.)
(https://www.legifrance.gouv.fr/codes/article_lc/LEGIARTI000006443524 )

The bonded installation method involves setting the tiles in a new cement mortar bed. This method is recommended for tiles with large or irregular surfaces. If the existing floor is uneven, the bonded installation method will level the floor, and the tiles will be laid in a single operation.
For regulations on sealed installation: ( https://carrelage.ooreka.fr/astuce/voir/615851/dtu-52-1 )

Adhesive installation involves laying ceramic tiles and tile adhesive directly onto a substrate. The substrate can be an existing screed, an existing ceramic tile, or any other surface suitable for laying ceramic tiles.
For regulations on glued installation: ( https://carrelage.ooreka.fr/comprendre/carrelage-colle )