If you have been placed on a waiting list, you will be contacted as soon as (and if) seats are vacant. Sometimes an organiser sells extra seats, or releases tickets which were booked earlier but for which payment was received late. It sometimes happens that seats that were initially provided for the entourage of the artist or the sponsors are released again.
There are various types of waiting lists, each with its own procedure.
1/ You will be sent a message in which you will be asked to contact the call centre or to make an online reservation.
2/ Or you will be sent a message in which you will be requested to make a provisional reservation final.
3/ Or you will be sent a confirmation of reservation, followed by a payment invitation.
Unfortunately, it is not possible for you to verify your position in the waiting list.