Valid on the metro network (M1, M2, M3 and M4) for a single short trip of up to 3 stops for a period of 30 minutes after validation. Trip interruptions and return trips are not permitted. During the period of validity transfers are allowed between metro lines M1, M2, M3 and M4 but only for a total of 3 stops. If you need to transfer to a replacement vehicle (e.g. in the event of cancellation, breakdown, track closure), you can continue your journey with the ticket already validated, but you must re-validate the ticket by stamping its end without the number grid with the validator of the replacement vehicle. Please show and hand over your ticket if requested by the inspector.
Please find more information here on the refund rule.