If you're planning a bit of sightseeing during your trip, head to Château de Voltaire— just one of the monuments in central Ferney-Voltaire. You could also start your cultural experience by heading over to the museums in the area. It's also full of great shops and restaurants, so you can spend the afternoon having a wander.
If you like haggling for the best price, you might want to head out to Ferney-Voltaire Market when visiting Ferney-Voltaire. There are also lots of shops and restaurants in the area if you fancy a wander.