Article 1645. Reduction of the creditor’s rights

(1) In so far as due to the creditor’s conduct the surety cannot be subrogated to the creditor’s rights against the debtor and to the creditor personal and proprietary security rights granted by third parties, or cannot be fully reimbursed from the debtor or from third party personal or proprietary security providers, the creditor’s rights against the surety are reduced by the extent necessary to prevent the surety from suffering any loss as a result of the creditor’s conduct. The surety has a corresponding right to recover from the creditor if the surety has already performed.
(2) The provisions of paragraph (1) apply only if the creditor’s conduct falls short of the standard of care which could be expected of persons managing their affairs with reasonable prudence.