The Front, which has three representatives in the European Parliament, hopes to get 15 to 20 European MPs, Le Journal du Dimanche quoted her as saying.
"We take part (in the election) to block the progress of the European project," Le Pen said.
Le Pen wants to drop the euro, is against the free movement of people in the union, and wants national sovereignty to take precedence over European legislation.
She said that many people do not vote in European elections because they are against the EU, but that this was the opposite of what they should do. "We are going to the very place we need to be ... a minority bloc that prevents more austerity and more loss of substance for France," she said.
The May election is expected to produce a surge in support for anti-EU parties on both the left and right, with some projections suggesting around a quarter of the 751 seats in the parliament could go to non-mainstream parties.
At a joint news conference in the Netherlands in November, Dutch Freedom Party leader Geert Wilders and Le Pen called for the creation of a new political group in the European Parliament after the May elections.