For all flights departing from Orly :
If someone forgot something at Orly airport (inside terminal landside or airside), they must go on Paris Aéroport Website to ask for it : https://parisaeroport-orly.franceobjetstrouves.fr/
For all flights arriving in Orly :
Any left over on board the plane will be given to Ground Handler by arrival agent.
Two options, either asking directly at Lost & Found Desk in Orly 4 upon arrival or go to the website https://troov.com where passengers can retrieve their property. Delivery of those items will be at their expense if they can't go to Orly to get those.