In the 30 days following the first round in the 1981 election, the French stock market dropped by over 20% as a result of concerns about the economic policies of Mitterrand, who eventually became president from 1981 to 1995.

Dembik says that if Marine Le Pen - who has an anti-Eurozone stance - wins, the same steep dive could happen to the CAC 40 by 20% after the election. The first round of voting is on April 23 and the second round is on May 7.