In Switzerland the legislation allows you to ride a converted bike without registration (yellow moped plate) up to 500w of engine power, and 25km/h of assistance (this does not concern the limit at which you can ride, you must respect the road traffic law in all cases)
If you exceed the assistance limit of 25km/h or 500w of engine power you can only use your bike on private property.
If you wish to ride on public roads with a motor of more than 500w or 25km/h, you must have your bike inspected by the motor vehicle department of your canton of residence. Before making such a purchase, please contact the motor vehicle department of your canton of residence for information.
Here you will find a list of the permitted regulations for electric bicycles.
French: Download the memento
German: Download memento