If you hire on the French side it's a bit cheaper, but I've just read something that says it's much easier to find your way back into the Swiss side of the airport to return it so it's worth paying the extra to hire from there.
Is this really true? And what about those pesky Swiss motorways that you need a permit for, is it possible to end up on one by accident and have to pay for the permit?
(We will be going to Chamonix btw so no need to be in Switz at all)
TIA