Many parties are concerned about hacking having an effect on the election, and there are questions about whether false material is mixed in with the email leaks, which are purported to be from four top-level members of the Macron campaign.
Macron is the front-runner in the the election, which is itself a runoff (with Macron and Le Pen combined receiving less than 50% of the vote in the first stage of the election.
In France, the media is not allowed to report on political topics 24 hours before the election begins.
Some are alleging that the hacks stem from the Russian government, which has been active in trying to influence other elections around the world. There is no hard evidence to support this, though, and no evidence is likely to be found, given the nature of the type of activity (cyber).