Here in Japan, I've never been to a place where you don't flush your toilet paper. In fact, they sometimes run into the opposite problem, with tourists not knowing you're supposed to flush the paper (https://www.japantimes.co.jp/news/2015/08/26/national/kyoto-...). Part of this might be because you're not supposed to flush sanitary napkins or anything but toilet paper, so there's often a bin next to the toilets for disposing of those, which I could see as confusing to someone who comes from a culture where you don't flush toilet paper.
Not uncommon in Europe either. Especially in non-renovated parts of old cities or middle-of-nowhere kind of places. Old pipes just can't handle too much paper.
Come to Baltic states or Poland then. It does happen in either super old and not yet renovated downtown buildings or roadside establishments in the middle of nowhere. Old narrow pipes just can't take paper. Especially if someone loves to fold it few times...
I think I've seen that in the UK as well, but memory may be playing tricks on me.