WE are going to Paris next April and would like to go to the opera or the ballet. How many days/months in advance of the performances do the ticket become available on the internet? We sure don't want to miss out. We are members of the Paris opera so we can order tickets once they are available.
I'm not positive about the Paris opera, but usually in Europe, tickets are avaiable once the next season gets announced. This usually occurs sometime in the summer or early fall. Unless there's a particularly famous singer or conductor performing, tickets generally aren't hard to get, including up to the day of the performance.