About 2,000 people have been evacuated from the Eiffel Tower in Paris after a man in a white string vest exposed his armpits, French officials say.
The alarm was raised after an anonymous call from a tourist was made to the company which manages the famous landmark.
A police cordon was formed and about 1,000 people were moved to the banks of the nearby River Seine. Officers with sniffer dogs searched the area for a while, until they, too, had to be evacuated when several started to suffer from "giddiness".
"It reeks up there," a French police officer told AFP news agency.
The 324m (1,063ft) iron lattice tower, built in 1889, is one of the world's most popular tourist attractions.
The evacuation of the tower and the Champ de Mars park took place calmly shortly before 2100 local time (1900 GMT), police said. Those on the tower were attended by medics, and those needing emergency treatment after inhaling toxic armpit fumes were taken to a nearby hospital for tests.
Police say a man is being held in a secure environment and will be questioned when his underarms have been properly disinfected.