Make no mistake, Brussels is deeply worried about the French presidential election.

If the right-wing populist and full-throated Euroskeptic Marine Le Pen pulls off a victory in the second round of the election on May 7, it could threaten the entire European project, making Brexit look like a walk in the park.

During a recent debate, Le Pen said she wants France to be a “true country” not “a mere region of the European Union.” And though she has appeared to walk back on the idea of taking France out of the EU wholesale, she recently said she still wants a referendum on membership. She has also argued that France should leave the eurozone as well as Schengen, restoring its border controls and reinstating a French currency.

That, however, is incompatible with continued membership of the Union. “There is no legal way to leave the euro or Schengen and still remain in the European Union,” said a Commission official.

In any case, if Le Pen wins the presidency, a vocal Euroskeptic would inhabit the Élysée Palace for the first time since the Union’s foundation. Most polls show Le Pen breaking through to the election’s runoff round in May, but losing to former Economy Minister Emmanuel Macron, who is running as an independent.

“From the Commission’s point of view, success for Marine Le Pen is a disaster and an existential threat to the European project,” a top Commission official said. “We can survive a Brexit, but not a Frexit.”

Fighting back against Euroskeptic claims

Given that the French election could have vital consequences for the EU, the European Commission is not taking any chances. In an unusual move, it’s getting involved in French politics, albeit indirectly, with a fact-checking campaign to counter the anti-EU narrative coming from Le Pen’s National Front.

The EU-paid fact checkers rebut Le Pen attack lines such as the assertion that France would be better off without the euro or that the EU destroys French purchasing power.

While the EU seeks to counter core Le Pen Euroskeptic messages, the Commission doesn’t endorse any specific candidate in the French race. But there is no doubt that Brussels insiders see a Le Pen win as a threat to the EU.

Pierre Moscovici, the commissioner for economic and financial affairs, said in a press conference last week that “it’s a mistake” to not to fight anti-EU candidates such as Le Pen. “Europe is France’s future, and we need France to be a driving force,” the French Socialist said, adding, in a clear swipe at the National Front leader: “I don’t even talk about those crazy ideas of France leaving Europe, which would both kill Europe and make France choke severely.”

Moscovici is not alone in his fear of Le Pen.

“It worries us — without any doubt,” said a top staffer in the Commission. “After the U.K. and the U.S. election, it would almost be a natural consequence.”

It’s not just in the Commission where fear of the far right is high. There is clearly no love lost between Le Pen and her fellow MEPs. In February, Le Pen sued Parliament and senior EU officials who are trying to recover hundreds of thousands of euros from the National Front leader for alleged misuse of funds.

The lawsuit targets the Parliament’s most senior civil servant, Secretary-General Klaus Welle, the head of the European Anti-Fraud Office (known as OLAF) Giovanni Kessler, and OLAF’s acting director of investigations, Beatriz Sanz Redrado.

Le Pen alleges that the investigation into misuse of funds was politically motivated — something the Parliament denies.

Paying close attention to Paris

Commission President Jean-Claude Juncker is following the French campaign closely, officials say. So far, he has conducted one-on-one meetings with three of the presidential candidates at their behest — the centrist Macron, the conservative François Fillon and the Socialist Benoît Hamon — and his aides are keenly watching the French polls and projections for voter turnout, a factor that could prove crucial. Polls predict around 65 percent turnout; the lowest in recent history was in 2002 at 71 percent in the first round. Le Pen hasn’t asked for a meeting with Juncker, an aide to the Commission president said.

For now, Juncker has stayed out of the fray, save for the occasional bullish quote. “The European Union will survive Marine Le Pen because she won’t become president,” he told Bild am Sonntag earlier this month.

Earlier this year, it looked as if Fillon, the candidate for the conservative Les Républicains, had the contest all sewn up. But his lead crumbled under the weight of a scandal involving his alleged use of public funds to pay his wife and children generous salaries for fictitious jobs as well as receiving seemingly questionable gifts from a lawyer.

Fillon’s backers in Brussels “are now looking at their shoes when talk turns to the election,” said a political aide from a Nordic country, adding it would be “unthinkable” in most EU countries for a candidate to stay in a presidential race under such circumstances.

The centrist and resolutely pro-EU Macron appears to have taken Fillon’s spot. Most polls put him roughly neck-and-neck with Le Pen in the first round but beating her comfortably in the second — to the expressed relief of officials in Brussels.

“The Commission would vote Macron without any doubt,” said a Commission top official.

But if disgruntled Fillon voters opt to stay at home rather than switch to Macron, or if Le Pen mobilizes otherwise apathetic voters, that could open the door for a National Front victory.

One top diplomat likened the vote to Brexit and last year’s U.S. election. The voters who decided the outcome then, he said, were “those who don’t give a damn anymore about politics.”

Several top EU officials confirmed there is no official “task force” to provide an EU response to a potential populist victory in France — not officially, in any case.

One diplomat joked that, if it exists, it is locked away in Brussels and Berlin.

“If there is a contingency plan, neither you nor myself would be able to get it,” the diplomat said.