Article 757 of Civil Code

1 - The surety shall not be discharged merely because the creditor has failed to take proceedings against the debtor when the debt falls due, or merely because he has delayed taking them. - Nevertheless, if the surety formally notifies the creditor to take proceedings against the debtor, the surety may request his discharge if the creditor does not take those proceedings within three months from the date of the notice, unless the debtor provides the surety with sufficient security. - The creditor's granting the debtor an extension without the surety's consent shall not preclude the surety's right to invoke his discharge.