On Monday French Industrial Renewal Minister Arnaud Montebourg said he did not want steel giant ArcelorMittal, controlled by India-born tycoon Lakshmi Mittal, in the country any more because it did not "respect" France.
Johnson, on a trip to India where he is drumming up investments in Britain, said he was amazed by the statement that he read in the Indian press on Tuesday morning.
"I see the sans-culottes appear to have captured the government in Paris," the Conservative mayor said.
"The French minister has been so eccentric to call for a massive investment to depart from France," he said.
"I have no hesitation in saying here, 'Venez à Londres, mes amis!' (Come to London, my friends)," he told a meeting of business leaders in the capital New Delhi.
"Come to the business capital of the world," Johnson added.
The "sans-culottes," meaning without "knee breeches", were the most militant supporters of the French Revolution at the end of the 18th century.
Johnson, a gaffe-prone politician whose popularity has soared after the successful London Olympics, added that a giant steel sculpture built by ArcelorMittal for the Games symbolised the friendship between London and India.
Lakshmi Mittal, who ranks 21st on the Forbes list of the world's richest people, is engaged in a fight with French ministers over plans to close a plant in the traditional heartland of France's steel industry in the eastern Lorraine region.