Thanks for the clarification.
I do not think there is an extra layer such as Sub Bank area within one unique bank area. At least not that I know of. So to me, there should be either account hierarchy option for interest compensation or a separate Bank area. If the requirement is only about the interest calculation, the account hierarchy option would suffice.
How do you record the sweeping movement between French subsididaries and French Local Master? do you use IHC to record the sweeping movement from bank statement, which the intereest calculation takes account of? I reckon if the sweeping movement is as such and the IHC to calculate the interest correctly, you would need to look at the creation of separate bank area only for FR and enlist the cross bank area posting as specified
573982 - Consulting note - cross-bank area posting
cheers
taro