Art.  2070.  If  the  guarantor  has  paid  without  notifying  the debtor,  and  the  latter  not  being  aware  of  the  payment, repeats  the  payment,  the  former  has  no  remedy  whatever against the  debtor, but only against the creditor. Nevertheless, in  case  of  a  gratuitous  guaranty,  if  the guarantor  was   prevented by a fortuitous event from advising  the  debtor of  the  payment,  and  the  creditor becomes insolvent,  the debtor shall  reimburse the guarantor for the amount paid. (1842a)

> GENERAL RULE—before the guarantor pays the creditor, he must  first  notify  the  debtor.    If  he  fails  to  notify  and  the debtor repeats the payment, the guarantor’s only remedy is to collect from the creditor but he has no cause of action from the debtor.

o     Creditor becomes insolvent
o     The guarantor  was  prevented by fortuitous event to advise the debtor of the payment 
o     The guaranty is gratuitous