I believe that we had tontine clause inserted when we bought our property 16 years ago. My wife is deceased, we do not have French wills and I would prefer to have the normal French succession law applied to our property. Is this easy to do?
I do not think this can be done retrospectively. Are you saying that your wife has recently passed away? If so, all sympathy to you at this sad time.
Unfortunately I think the notaire will have to apply the rules in line with whatever the situation was at the time of your wife's death. If the tontine clause was in force at that point, it would be too late to change it now.
I am 99.99% sure, because for one thing any change to a contract that you both signed would require your wife's signature, but it is worth asking the notaire.