When you are seeking the services of a tradesman the likelihood is that you will ask for recommendations from people that you know or from your local magazine. Don't take these at face value. There are a number of obligations that you need to consider before anyone crosses your threshold and commences work, as there are serious implications for the homeowner should you choose to use unregistered or uninsured trades people on your premises.
There are a number of sites that you can visit to check siret numbers :
https://www.infogreffe.com/societes/
http://www.manageo.fr/
http://www.societe.com/
However, please note that these sites will only provide details of the main and primary activity and not any subsequent activities. If in doubt, feel free to call your local Chambre de Metier and ask them to verify what they are registered as, or enquire with your local Mairie.
Don't be afraid to ask to see attestation or confirmation of the relevant insurances attributed to trades. Who is the insurance with? Are payments up to date? We all know France loves a law and insurance. Each activity needs to have the corresponding insurance. Insurance for one activity does not cover for all. Please note that there is difference between public liability insurance and decennale insurance and some trades are required to have both. If you have doubts, eliminate them from your research.
Artisan tradesman are required to have decennale insurance and a carte professionnelle – this provides confidence to a potential customer that they have had their qualifications verified by the Chambre de Metier and are appropriately insured. Plus artisan tradesmen are not allowed to register additional activities. For example as a registered artisan electrician you won't see me offering to cut your grass.
Devis and factures will need to show siret number and insurance details, these are recent requirements, so if you don't see this on any paperwork, again feel free to eliminate from your research.
Devis should be clear and set out exactly what will be done. Do not sign a devis until you are happy that everything you want done is included. There should be no hidden surprises between devis and facture. Be clear about when works are to commence, particularly when there are a number of trades involved.
A reputable tradesman will ask for a deposit or materials to be paid.
A reputable tradesman will clearly state how future payments are to be made.
A reputable tradesman will not insist on being paid cash.
A reputable tradesman will happily give you references of customers that you can contact if you request to do so.
A reputable tradesman will have more than just a mobile number to be contacted on.
It is not unusual to seek 2 or 3 devis and a reputable tradesman will be aware of that. You as a customer should be able to ask questions and feel confident about who you are dealing with, as ultimately they will be working in your home and you will be paying them. So any doubts or concerns you have eliminate them from your research.
Always work with a reputable tradesman, there are serious implications as a home owner should an unregistered or uninsured or not appropriately insured tradesman be working in your home. Should an accident or death take place in your home, you as the home owner will bear some responsibility.
Should you wish to sell your house you may be asked by the Notaire to provide invoices for major works that have been carried out within a certain timespan. If you are unable to do this, you may find yourself footing a bill should something untoward happen in the future once your home is sold.