La. Civ. Code § Art. 2676

Art. 2676. Agreement as to the rent
The rent shall be fixed by the parties in a sum either certain or determinable through a method agreed by them. It may also be fixed by a third person designated by them.
If the agreed method proves unworkable or the designated third person is unwilling or unable to fix the rent, then there is no lease.
If the rent has been established and thereafter is subject to redetermination either by a designated third person or through a method agreed to by the parties, but the third person is unwilling or unable to fix the rent or the agreed method proves unworkable, the court may either fix the rent or provide a similar method in accordance with the intent of the parties.