Transcript for French presidential election hack

Next to that key presidential showdown in France tomorrow and a headline that may sound very familiar -- a quote, massive and coordinated on the candidate leading in the polls in an apparent effort to help the nationalist candidate. ABC's Terry Moran reports from Paris. Reporter: At the 11th-hour in this bitter campaign, a stunning development that massive computer hack of the campaign of front-runner Emmanuel macron. Have you heard about the wikileaks hack of the macron -- We have heard about it. This is an awful word I think it's From LE pen. Reporter: It consistents of professional and personal e-mails and documents from the macron campaign. Warning the media to limit coverage of the hack because the free expression of voters is at stake. Voters we spoke with in France were deeply suspicious and even angry about this cyberattack. Hillary Clinton e-mails were hacked. Do you think is the same kind of thing? Same people? We don't know, we don't know. Because -- but it's very strange. Reporter: The drama comes at the close of this campaign, a race where the themes echo the American election last year. Marine LE pen, a hard-right nationalist, anti-european union, anti-immigration, anti-islam. And macron, pro-eu, pro-immigration, more tolerant. He got a last-minute, and highly unusual, endorsement from former president Barack Obama. I am supporting Emmanuel macron to lead you forward. Reporter: President trump, while saying he was not explicitly endorsing either candidate here, told an interviewer LE pen is "Strongest on borders, and she's the strongest on what's been going on in France." The final poll shows macron ahead by 20 points and LE pen sagging. This hack probably won't affect the outcome but it could damage macron if he wins. Terry Moran tracking the election out of Europe.

This transcript has been automatically generated and may not be 100% accurate.