Sorry, I have no idea what your trying to say. Did I mention anything about changing /etc/named.conf or /var/named/france-tracker.zone ? No, I told you the steps in the grafical interface of ISPConfig, which I assume you use, as you posted your question in the ISPConfig forum and you state "ISPConfig & postfix error".
Please do the steps as I described in my previous post in ISPConfig and the actual files will be modified in the right locations in the right place for you. No manual editing. If you get errors, we'll start over from there.
Without a MX record, you will never receive email from the internet.