Two or more parties who are liable for one and the same performance are (a) joint, or (b) partial debtors. Parties are liable as joint or partial debtors when they unite in making one and the same promise under the same contract or when they are liable for the same damage unless the contract or the law provides otherwise.
(a) Joint debtors
(aa) The creditor may claim performance from any one of the joint debtors until full performance has been reached.
(bb) If one joint debtor has performed, in kind or by way of set off, the liability to the creditor of the other joint debtor(s) is discharged to the extent of such performance or set-off. The same applies if one joint debtor concludes a settlement with the creditor.
(cc) As between themselves, joint debtors are liable in equal shares unless the contract or the law provides otherwise. If a joint debtor has performed more than his share, he may claim the excess from any of the other joint debtors to the extent of each debtor's unperformed share.
(dd) A joint debtor may invoke against the creditor any defense which another joint debtor can invoke, other than a defense personal to that other debtor. Invoking the defense has no effect with regard to the other joint debtors.
(b) Partial debtors
(aa) The creditor may claim from any partial debtor only that part of the performance for which he is liable and the partial debtor is bound to perform only to that extent.
(bb) Partial debtors are liable in equal shares unless the contract or the law provides otherwise.