The swapped seasons are a real mind-bender eh? I instinctively feel that it makes more sense to start and end the year in summer, but that's just what I'm used to. I guess Europeans get summer and Christmas holidays six months apart from each other, which is a huge plus.

I think at least 20% of posters in the Paris metro are of cultural events, but that's just a totally random estimate. It seems to depend on the metro station too — some metro stations seem to have more culture ads than others