Former French Economy Minister and candidate for the left-wing primary ahead of the 2017 presidential election Arnaud Montebourg looks on as he attends La Fete de l'Humanite in La Courneuve, near Paris, on September 10, 2016. / AFP PHOTO / Thomas SAMSONTHOMAS SAMSON/AFP/Getty Images

Greece's far-left former finance minister Yanis Varoufakis (2nd L), his wife Danae Stratou (L) and Former French Economy Minister and candidate for the left-wing primary ahead of the 2017 presidential election Arnaud Montebourg (R) attend La Fete de l'Humanite in La Courneuve, near Paris, on September 10, 2016. Decided candidates running for the Presidential elections, trade unions against the labor law: La Fete de l'Humanite (Humanity Festival) announces a troubled autumn for the left wing. / AFP PHOTO / Thomas SAMSONTHOMAS SAMSON/AFP/Getty Images

Former French Economy Minister and candidate for the left-wing primary ahead of the 2017 presidential election Arnaud Montebourg (R) looks on as he attends La Fete de l'Humanite in La Courneuve, near Paris, on September 10, 2016. Decided candidates running for the Presidential elections, trade unions against the labor law: La Fete de l'Humanite (Humanity Festival) announces a troubled autumn for the left wing. / AFP PHOTO / Thomas SAMSONTHOMAS SAMSON/AFP/Getty Images

Former French Economy Minister and candidate for the left-wing primary ahead of the 2017 presidential election Arnaud Montebourg looks on as he attends La Fete de l'Humanite in La Courneuve, near Paris, on September 10, 2016. Decided candidates running for the Presidential elections, trade unions against the labor law: La Fete de l'Humanite (Humanity Festival) announces a troubled autumn for the left wing. / AFP PHOTO / Thomas SAMSONTHOMAS SAMSON/AFP/Getty Images

Former French Economy Minister and candidate for the left-wing primary ahead of the 2017 presidential election Arnaud Montebourg reacts during La Fete de l'Humanite in La Courneuve, near Paris, on September 10, 2016. Decided candidates running for the Presidential elections, trade unions against the labor law: La Fete de l'Humanite (Humanity Festival) announces a troubled autumn for the left wing. / AFP PHOTO / Thomas SAMSONTHOMAS SAMSON/AFP/Getty Images

French Economy Minister Emmanuel Macron attends a political rally for his recently launched political movement, En Marche!, or Forward!, in Paris, France, July 12, 2016. REUTERS/Benoit Tessier/Files

US-British microeconomist and 2015 Nobel Prize winner in Economics Angus Deaton poses during an interview in Paris on September 8, 2016. Nobel prize winning economist Angus Deaton says billionaire Donald Trump's US presidency campaign and Britain's shock vote to quit the EU are symptoms of a botched drive to integrate globally. In an interview with AFP, the British-US poverty expert warned that the Republican candidate in November's US elections was "not a good voice" for those neglected by the global movement towards economic and financial integration. / AFP PHOTO / ERIC PIERMONTERIC PIERMONT/AFP/Getty Images

US-British microeconomist and 2015 Nobel Prize winner in Economics Angus Deaton poses during an interview in Paris on September 8, 2016. Nobel prize winning economist Angus Deaton says billionaire Donald Trump's US presidency campaign and Britain's shock vote to quit the EU are symptoms of a botched drive to integrate globally. In an interview with AFP, the British-US poverty expert warned that the Republican candidate in November's US elections was "not a good voice" for those neglected by the global movement towards economic and financial integration. / AFP PHOTO / ERIC PIERMONTERIC PIERMONT/AFP/Getty Images