Create a loss report online:
You can create a loss report yourself 24/7 and describe your item. You will then receive matching suggestions.
Is your item already on this list? Perfect: contact the relevant lost and found office and collect your item.
If the item is not (yet) displayed in the lost property list, you can search again later. If the item is handed in to the lost and found office in the meantime, they can contact you very quickly based on the loss report you created.