minesthechevy, as I understand it, it is even worse than a simple breach of the obligation to counsel and inform the mundane.
First, keep in mind that it is not certain at all that you have passed a contract even if you have signed a "bon de commande" because the name on the document is not binding and depending on the factual situation said document can be interpreted as a request for an offer or as an acceptation of an offer. A valid contract will only exist in the second eventuality (N.B. in French law there is nothing like consideration, a contract is passed as soon as an offer is accepted).
Lets assume that you have passed a K with these companies. Then the question will be "which kind of K?". It could be a "contrat d'entreprise" (i.e. asking someone to "build someting for you according to specific parameters") or sort of "a pre-contract" for a study prior to the work (contrat de services). In this respect, I recommand you to ask these companies to precise wich obligation they consider you have contracted. Be careful, while doing so never admit that you are binded as it would be considered as "acquiessement"! Your "defense" will depend on their answer. If they ask you money only for the study it will be more difficult to avoid the "obligation" (provided there is a K). If they ask you to commit yourself for the work (and pay for it) you will be in a position to claim that the contract (if any) is not valid.
According to my understanding of the facts, the eventual K has been "vicié" (rendered irregular) either for (1) "dol" (fraud) on the ground that they lured you in signing a "bon de commande" for a work when you only requested a study or (2) "erreur" (mistake) as you were confused on the "substance" of the object of the K (i.e. study vs work).
According to Art. 1109 of the Civil Code a contract is void if the consent was given in "erreur" or because of "violence" or "dol".
According to article 1110 of the Civil code, to be sufficient to void a contract an "erreur" should concern the "substance" of the thing that is the object of the K (i.e. never the price).
According to article 1116, "dol" is enought to void a contract when it is clear that the "victim-party" would not have signed without the "manoeuvres" (trick) of the other party.
If you need the services of a French lawyer you would better consult (and later appoint if needed) a territorialy competent Avocat (i.e. from the Bar where the possible K was signed or from the Bar where one of the companies have its commercial seat). Keep also in mind that free consultations with an Avocat are available usualy in places like Mairies, Maisons de la Justice et du Droit, Courts, Bar...
Good luck!