There are several European countries (Ireland, Norway) where you're not allowed to smoke in public bars. However, the law isn't explicitly against smoking in bars, it just says that smoking at the work place is prohibited - and bars are the working places of bar tenders and waiters.
The obvious solution would be to create automatic bars - places where nobody works and you can buy the beer by tossing coins into a slot machine. Or put the barmaids into a plexiglass box where they can breathe fresh air while their customers can smoke. The glass box would have a "beergate" so they could pass out beer without having to breathe the same air.
Reward: Free beer at the pubs