France's far-right National Front party leader Marine Le Pen finished a strong third in the first round of presidential elections last month.  Now, her supporters may be key in determining the outcome of the runoff vote May 6 that pits French President Nicolas Sarkozy against front-runner Socialist rival Francois Hollande.  

The thousands of National Front supporters attending the party's traditional May Day rally in Paris were in a festive mood.  They cheered as the party's leader, Marine Le Pen, celebrated her third-place finish in the first round of French presidential elections and they booed as Le Pen mocked the two finalists in next Sunday's runoff vote - French President Nicolas Sarkozy and Socialist party challenger Francois Hollande.

Hours later and several kilometers away from the National Front rally, President Sarkozy held his own May Day gathering in Paris.

In interviews like this recent one on French radio, Sarkozy says it is important to listen to French who voted for the National Front.  Theirs is a call of anger and despair, he says, at a time when the French economy is ailing and unemployment is close to 10 percent.

Le Pen is not endorsing President Sarkozy or Hollande.  And her supporters, like student Helene Justin, are uncertain about how they will cast their ballots.

Justin says she is not really happy with either choice.  Justin says that as far as she is concerned, the two are about the same and only care about the elite.

Retiree Gerard Virginier expressed similar sentiments.

Virginier says he is turned off by both candidates, but especially by Sarkozy.  He accuses Sarkozy of stealing the National Front's agenda when he first ran for office in 2007 - and then failing to honor it as president.

During these tough economic times, many French have identified with the National Front's anti-European Union and anti-immigration message.  Nearly one in five voters cast ballots for Le Pen in the first round.

How they vote in this runoff may determine its outcome. Sarkozy is expected to lose without a massive amount of National Front support.

Analyst Philip Whyte is with the Center for European Reform, in London.

"In the campaigning in the second round, Sarkozy has definitely been flirting with the voters of the National Front," said Whyte. "And that's manifested itself in two areas in particular.  The first is on immigration - he's been making some relatively hostile remarks on immigration.  And second, he's been making much more protectionist noises on economic policy."

Polls have suggested Sarkozy will be defeated in Sunday's final vote. Sarkozy has just days to convince National Front voters to back him for another term.