I'd imagine that the reason Japan would have signage in English would be that barely any non-Japanese/Chinese speaking people in the country would be able to understand the text, so if a translation is needed it may as well be in the most widely-used Roman script language. Elsewhere in the world I think signage is not that much different to Australia for monolingual nations.

And I'm surprised any of you have managed to get anything other than Français out of the French. I've never been to Paris though.