The far-right candidate has promised to put a Frexit vote to the public should she win the election. If France votes out of the euro, markets fear it could spell the end of the project.
After last year's surprise Brexit vote and Donald Trump win, investors are anticipating the French could deal the establishment another blow.
FXTM research analyst Lukman Otunuga, said: "Markets simply acknowledged this fresh development as potentially heightening the chances of Marine Le Pen winning the elections which consequently exposed the Euro to further downside losses on Tuesday.
"Sentiment remains firmly bearish towards the Euro moving forward and the growing threat of a possible “Frexit” challenging the future of the European Union should limit future gains.
"From a technical standpoint, the EURUSD remains heavily pressured on the daily charts."