Three siblings signed the admission papers for their mother at a nursing home, believing the costs would be shared equally if any problems arose. However, several months later, an unpaid debt accumulated, and the facility contacted only one of the three children, demanding the full amount owed without considering the distribution among the co-signers. This situation, while legally allowed, often surprises families. The solidary guarantee allows the nursing home to demand the entire debt from a single signatory, leaving that person to seek contributions from the others. A solidary guarantee is a legal mechanism where one or more individuals agree to be fully responsible for a debt, even if others are also involved. This is different from a security deposit and an alimentary obligation, which are separate concepts. Before signing, it is possible to negotiate a maximum amount or a limited duration for the guarantee. If not specified, the guarantee remains unlimited in both amount and time. The solidary guarantee is commonly requested by nursing homes during admission. On paper, it seems harmless, with each person assuming they are only committing to their share. In reality, the opposite is true: as soon as there is a month of non-payment, the facility can contact a single guarantor and demand the entire debt. It then becomes the responsibility of this person to turn to their siblings for their share. The nursing home has no obligation to divide the amount in advance and can choose whom to contact. An important detail is that, unless otherwise stated in the document, the guarantee is unlimited in both amount and time. Recent court decisions illustrate this mechanism, such as a solidary condemnation of nearly 57,000 euros against a son guarantor, while another claim was dismissed due to insufficient evidence of the bills. The security deposit is a sum paid upon entry, capped at the monthly housing rate, intended to cover any damages detected upon departure. It must be returned within thirty days following the resident's departure, after deducting any possible claim. The solidary guarantee, on the other hand, refers to a person who guarantees payment, not a sum of money. The alimentary obligation, provided for by the Civil Code, exists independently of any signature: it applies between parents and children even without a guarantee document. Its particularity is that its amount is never set by the facility but by a judge, according to a proportionality rule between the parent's needs and the resources of the person who must contribute. This obligation comes into play particularly when the resident applies for housing assistance, and the judge then evaluates the contributory capacity of each child on a case-by-case basis. Before signing a solidary guarantee document, a few simple checks can prevent many unpleasant surprises. It is possible, for example, to negotiate a maximum amount or a limited duration for the commitment, provided these conditions are clearly stated in the document. Without this, the guarantee remains unlimited by default. It is also important to keep in mind that the document binds the signatory for all debts incurred until the resident's definitive departure, and that in the event of death, the guarantee remains responsible for unpaid bills prior to that. Refusing to sign is possible, but may result in a refusal of admission to a facility not authorized for social assistance. However, for nursing homes authorized for social assistance, the signing of a guarantee cannot condition admission, and for beneficiaries of housing assistance, the commitment can only cover the portion of the rate remaining the resident's responsibility. These nuances are worth checking line by line before the signature definitively closes the door to any negotiation. Between a poorly read document and a misunderstood commitment, the solidary guarantee reminds that entering a nursing home can have unexpected legal pitfalls. Rereading each clause, questioning the facility, or even consulting a family law professional: these precautions are well worth the time invested. Because once the signature is made, it is often too late to go back.