La. Stat. tit. 17 § 424.2
Any teacher holding a valid Louisiana teaching certificate at the time of rendering teaching services for which he was properly certificated in a private elementary or secondary school approved by the State Department of Education shall receive experience credit for such services under the state minimum salary schedule provided for in R.S. 17:419-422 when employed by any parish or city school board or by any special school in Louisiana; provided, however, that he shall not receive credit for such teaching services for any year in which he was not properly certificated for the services which he performed, nor shall he receive credit whether certificated or not for teaching services rendered in any year in which the private school employing him was not approved by the State Department of Education.
La. R.S. § 17:424.2