Common sense
I assume tens of thousands of Japanese visit Paris every year. I expect it's not unlikely that of this number, a dozen are going to have psychological problems. In fact, they would probably have had the same problems in any tourist destination. This is probably a non-story.
Frankly, I didn't have to read too many manga to come to the conclusion that a lot of Japanese are just this side of the bend in the first place. ;)
As I have said before, I saw no unfriendly or rude behavior when I was visiting France, and if I didn't inspire it, who would?