Hello JeanPepito
The SBB Community is not the right place to make people aware of a lost items.
As per law, items found on a train must not be taken home by an individual. They must be handed over to the train operator’s lost & found service.
Consequently, the only way to get it back is through a lost property report. It may take up to 3 weeks to have some news.
https://lostandfound.sbb.ch/home/sbb/SBB/app?Culturename=en
Kind regards,
Roland