I would do some research on the internet.

https://www.beobachter.ch/konsum/kon...mahnt-grundlos

https://www.konsumentenschutz.ch/for...istungskosten/

First try to validate if it could have been you.
Then check what's the fine for less than 10 km/h over the limit. Even 111 CHF seems massive to me.

Then tell them you need the original fine and you only intend to pay as much as the fine was. Then pay the original amount and be done with it.