Many people in this part of Switzerland do their shopping in France due to the lower prices. We decided to check it out today. We drove towards Geneva and then headed north for about 3km. There was an official border crossing, but it wasn't staffed. The grocery store was very crowded. It had way too many people and the aisles were narrow. We decided that the prices on meat (specifically chicken) are much lower in France, but I'm not sure if the lower price offsets the gas expense. The store did have a much better selection of baby food than we've been able to find here, so we may need to go back and stock up once in a while.
We took a different route home and didn't even see a sign marking the border.