Getting out of lease and Loi Montagne Article 42

Hi,

We are hoping to exit our lease in 2 years time.  It is with CGH.  This is an extract from an email from CGH when enquiries were made made about the terms of exiting the lease:

De plus, le proprietaire se verra solliciter d'une indemnité d'éviction (deux à trois ans de Chiffre d'affaires) si d'aventure il ne souhaite pas renouveler son bail 

A cet instant je ne connais pas la composition de la Loi Montagne et de son article 42 pour ce qui concerne *************.

Il est de € 497,- le m² pour la Rosière (73), par exemple.

We know about the indemnity fee and although it is not what we were anticipating, we are considering paying it so that we can have full use of our apartment as promised when we agreed to buy it.

What I don't understand is this mention of Loi Montagne article 42 which is apparently 497 euros per square metre for la Rosiere.

Can anyone shed any light on this?  Would this be an additional payment to the indemnity fee - in which case it makes a huge difference to the cost of exiting the lease?

Any thoughts much appreciated.