This means that should you have a problem with the standard, finish, completion of the work in question, it may be very difficult to get any redress. It is also quite possible that these operators have no insurance…
We recently received a devis (quotation) from a S.A.R.L. registered company, that had no siret/siren number. That company was quickly discounted, because they could not produce their registration number and worse, they could not produce a current certificate of insurance.
If you have doubts about a company in these matters, you can check their status, with the Chambre de Metiers in their Department .
Enjoy your life in France - we most certainly do!
My advice, even if the company has a SIRET/SIREN ask for a copy of the insurance because if they go out of business you can contact the insurer yourselves. Without the client/contract number the insurance company won’t be overly helpful is our experience so far when we found ourselves in the position of needing to claim on assurance decennale for a tradesman who went out of business.