Is it mandatory to schedule a break before a reservation? What is the minimum rest time before a flight duty carried out on a booking?

In accordance with the regulatory point ORO.FTL.230; ORO.FTL.235:

Before a FDP period, you must always give the required rest in ORO.FTL.235 (12 hours on base, 10 hours off base or the previous activity if higher). Therefore, if there is no such rest before the reservation, this rest must be guaranteed between the notification of the activity and the report. NOTE: The above reply corresponds to an assigned FDP during the first day of booking. If it is an assigned FDP during a booking day preceded by a booking day on which no activity assignment has occurred, the 10-hour notification of the reservation would be sufficient.