My husband's family is coming over next week and they are renting a car from Zurich and driving to a few places that cover Germany, Austria and France. Just wondering if there is a similar vignette to what Switzerland has for their highways that cars have to display? Tried asking at the car rental agency but the person wasn't much help (waved their hand and said we should know the rules where we are going to drive

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just don't want them to get stopped and charged some high fine for something with a simple solution!
Thanks!