This can't be quite true. In Berlin smoking is prohibited in public buildings, public transportation including nearly 100% of all train stations (the exception being designated smoker areas of ~20m² on open-air platforms), shops, bars and inside restaurants. Many places offer open-air seating (they call it Terrasse but it's the sidewalk); there, being outside smoking is not prohibited. There's an exception for small-ish bars which are clearly marked as being smokers' places and for adults only (>18yrs). So I'd say you've got a good chance of not getting smoke blown into your face.

Also, while you're right in that comparatively many people in Berlin are smokers (although that might be a commonality of cities as opposed to the countryside), they're still a minority of <30% [1], so more like 1/3 than 3/4 (it can feel like every second guy in the street though).

[1] https://www.abnr.de/tabakpraevention/daten-fuer-deutschland/...