Hello, we rode a RER A train from Bussy-Saint-George around 5.20 am on 03/09/18 and got off at Gare du Lyon. Unfortunately, we left a disneyland bag with our photos and some toys for the kids. I wonder if there's anyway we could get it back. We are already in Ireland. Thank you for your kind consideration and reply in the future.
Lost and Found for Paris Metro and RER A/B might be able to help you locate the item, but as far as I understand collection of the items would need to be done in person either directly with the RATP (transit authority) or with the Paris Police Station in the 14th arrondissement which handles lost and found beyond 15 days after the incident.