The new Air France cancellation policy allows you to change your flight/trip without penalty, regardless of the fare limitations on your ticket.
You must amend your plans up until the day of your first flight's departure.
You are free to change your travel date and/or destination at any time.
If your new ticket is more expensive (or the original fare is no longer available), you will only be responsible for the difference if fares and taxes are the same (if any).
Most ticket adjustments can be made online using My Bookings. Contact online customer service if you are unable to do so.