French police said initial tests showed the contents were non-toxic and that the alert was now over.

Officers wearing decontamination suits had evacuated the building in the centre of the French capital and closed off the Avenue Montaigne.

The package contained a piece of tissue soaked in an unknown fluid.

"We don't know what it was but it's not a toxic substance," said Florent Hivert, a spokesman for the Paris fire bridge.

He said the scare, which triggered an alert for possible radiological, bacteriological and chemical danger, was now over.

Reporters said the area surrounding the building, on one of the city's smartest streets, was blocked off and fire engines and police officers were present.