As far as I understand that, since there is no explicit clause prohibiting an extension after 6 months. I think it is safe to assume that it can be extended by

As far as I understand that, since there is no explicit clause prohibiting an extension after 6 months. I think it is safe to assume that it can be extended by another 6 months provided the suspicion persists (i.e. a judge can be convinced). I'm not french myself, so take it with a grain of salt.