Paris syndrome is a rare, acute form of culture shock documented mainly among Japanese visitors to the French capital. Its psychiatric symptoms include delusional states, depersonalization, derealization and a conviction of being persecuted by locals, and its physical ones include dizziness, sweating, vomiting and a racing heart. A 2004 paper by Viala and colleagues in the French journal Nervure named four causes: the language barrier, friction between harmony focused Japanese etiquette and informal Parisian manners, exhaustion from long flights and jet lag, and the gap between an idealized Paris and a crowded, littered, pickpocket prone city. A 2016 paper split sufferers into those with prior psychiatric history and those with none who develop a delayed stress reaction.

The clash is old. Sir Thomas Browne warned in 1656 that weak constitutions should avoid cities like Paris and Rome, and in 1732 Jean-Jacques Rousseau expected marble and gold palaces but found stinking streets, black houses and beggars, an aversion he said never left him. Japanese psychiatrist Hiroaki Ota named the syndrome in the 1980s while treating patients at Sainte-Anne Hospital and published a book in 1991. In 2006 outlets including the BBC reported a Japanese embassy emergency hotline and repatriation flights, which the embassy denied. The real figure is about three to five hospitalizations a year among roughly 1.1 million Japanese visitors.

• How a surge of arrival excitement gets reinterpreted as panic when reality fails the brain’s predictions
• Mario Renoux of the Franco-Japanese Medical Association blaming advertising for a city of ghosts
• Chinese tourists reported leaving Paris in tears by 2014
• A 2012 Paris tourism office survey citing safety and cleanliness, and police translating their website into Chinese
• Graziella Magherini’s Stendhal syndrome in Florence as the mirror image, triggered by overwhelming beauty