Call Allo TAG on 04 38 70 38 70 (in French only - price of a local call) between 8.00 am and 6.30 pm Monday to Saturday, to see whether the item has been found.
It will then be held under your name.
You will be able to collect it between 8.00 am to 6.30 pm Monday to Friday at:
agence de Mobilité
49 avenue Alsace-Lorraine
Get there with the A, B, E, C1 and Transières lines | Alsace-Lorraine stop