Article 21 of Decree-Law No. 15 of 1979 concerning the Civil Service

The right of the governmental entity to recover amounts paid by it to an employee without entitlement shall be time-barred upon the expiry of 5 years from the date of disbursement. The limitation period provided for in the preceding paragraph shall not apply if disbursement was made as a result of fraud or deceit by the employee. The employee's right to claim the financial entitlements prescribed for him shall be time-barred upon the expiry of 1 year from the date he becomes aware of those entitlements or 5 years from the date of entitlement, whichever period expires earlier. Any written claim for the foregoing amounts and entitlements shall constitute a ground for interrupting the limitation period provided for in this Article.