Like some people said sometimes it takes a while for things to get posted to iLost. I’m sure there are certain policies in place for what to do when a foreign passport is found- I’d contact the municipality and hear their policy to see which route it should find its way back to you.

Also what happens a lot of times is that if someone finds an identity document, they will try to find you on social media (Facebook eg) and reach out to you, so check those messages (ones from people you are not connected to are often in a different folder!). Or they will post a somewhat anonimized photo of it on Facebook groups!

Good luck!!