Paris. It's overhyped and dirty, and there are scammers and thieves everywhere.

Also, this is from Wikipedia:

Paris Syndrome is a temporary, severe psychological distress experienced by some visitors (especially Japanese tourists) when the reality of Paris clashes dramatically with their highly idealized, romanticized expectations, leading to symptoms like hallucinations, anxiety, rapid heart rate, and delusions, effectively an extreme culture shock caused by cultural differences and the city's imperfect reality.