Article A322-156 of the French Sports Code
For jumps defined in 1° and 2° of articles A. 322-150 and A. 322-151, the landing zone is clear and at least one hundred metres in diameter. In addition, its surroundings allow safe landings outside the zone. For jumps defined in 3° of articles A. 322-150 and A. 322-151, the landing zone is clear and at least fifty metres in diameter.