Police help keep the peace.

Considering how the Swiss dislike noise, why not? (A man in his castle is entitled to some peace and quiet in the evenings, no?) I'm sure if you're the OP, you could be annoyed as hell and want to do something about it, too, and not wax lyrical about the joys of childhood footie after dusk or call practical advice sad.

Sure you can go ask the parents and all that, but remember what happened to the man who had to deal with kids ringing his doorbell?

Just a friendly word with the police and from the police can do wonders in a society that respects law and order. No one else can help or will help the OP.