+1

You'll find that throughout Europe, a Compact is much smaller than what you'd get in the same class in the USA.

I'd recommend that you go with one of the major rental companies - preferably one where you have status if any - or at least book a flexible rate. That way you can see which specific cars are available on the day. Even within the same class, cars could differ quite widely, so this is the only way to get one that you'll be comfortable with.

Many of the majors will allow you to contact the rental location directly, and they can be quite amenable to requests, but the level of service really depends on the local manager.