@SafeTex: indéfiniment is not "until he kicks the bucket," it is, as Adrian said, without limit as to the amount -- i.e. they could lose everything they have in the world, not just everything they invested in the business.
When a company goes belly up, shareholders/investors can only lose the value of their shares/investments; they might lose everything they put into the company, but all their other property (house, car, bank accounts etc.) is protected.
Partners, however, are jointly liable for the company's debts, up to the entire amount of all the property each partner owns in the world. That's what indéfiniment means here: even if you only invested $10, you are still fully on the hook, to the maximum extent possible, for the company's debts.
"La responsabilité solidaire signifie qu’un créancier peut poursuivre un seul associé de la SNC [société en nom collectif] pour la totalité d’une dette. La responsabilité indéfinie implique que les associés sont responsables sur l’ensemble de leurs biens personnels."
https://www.economie.gouv.fr/entreprises/societe-en-nom-coll...