À quoi correspond le statut « En attente » d'une réservation ?

Here are some reasons why your reservation might have a "Pending" status:

The host needs to respond to your request

When you make a request to book and complete your payment, a reservation request is automatically sent to the host, who has 24 hours to accept or decline the request. The status for your reservation will be "Pending" until the host responds. During this time, you can also contact the host to approve your request. 

If the host declines your request or doesn't respond within 24 hours, the booking status will be updated as "Declined" or "Expired," and your payment will be refunded to your original payment method.

You need to complete identity verification

Sometimes a reservation will be "Pending" if you've booked a place to stay but you haven't completed the identity verification process. In this case, you'll have 12 hours from the time you booked to complete identity verification, otherwise the reservation will be automatically canceled.