According to Reuters, approximately 12 Japanese people a year require psychological treatment after visiting Paris.It is mostly down to unfriendly locals and scruffy streets. 

Fragile travelers can lose their bearings. When the idea they have of the country meets the reality of what they discover it can provoke a crisis.

said psychologist Herve Benhamou.

This year there was a case where two women became convinced that their hotel room was bugged and there was a plot against them going on.

In the past there were also instances where a Japanese man became convinced he was Louis XIV and a woman believed she was being attacked by microwaves.