The attack came 36 hours before the nation votes today in a crucial presidential runoff between Macron and far-right candidate Marine Le Pen.
The commission met early yesterday after reports of the hacking attack emerged just before midnight on Friday, when a pause in campaigning is required.
It said the leaked data apparently came from Macron’s “information systems and mail accounts from some of his campaign managers”. It said the data had been “fraudulently” obtained and fake news had probably been mixed with it.
The commission urged French media and citizens not to relay the leaked documents “in order not to alter the sincerity of the vote”. French electoral laws impose a news blackout on any campaigning and media coverage seen as swaying the election in the 44 hours preceding a vote. This started on Friday at midnight.
The perpetrators of the hacking attack remain unknown and it is unclear whether the document dump would dent Macron’s large poll lead over Le Pen.
Fears of hacking and campaign interference have simmered throughout France’s high-stakes, closely watched campaign – and they boiled over on Friday night as Macron’s team said it had been the victim of a “massive and co-ordinated” hack.
It said the unidentified hackers accessed staffers’ personal and professional emails and leaked campaign finance material and contracts – as well as fake decoy documents – online.
In a cursory look at the leaked documents, they appear to be largely mundane day-to-day communications, with a few items so out of character that they might be fakes. Other documents, which seem to date back several years, do not appear related to the campaign at all.
The Macron team’s announcement about the hacking attack came just 10 days after the campaign’s digital chief, Mounir Mahjoubi, said it had been targeted by Russia-linked hackers – but that those hacking attempts had all been thwarted.
Mahjoubi did not respond to requests for comment amid the campaign blackout yesterday.
Florian Philippot, the number two in Le Pen’s anti-immigrant National Front party, asked in a tweet: “Will the #Macronleaks teach us something that investigative journalism deliberately buried?”
Meanwhile voting for France’s next president started in some overseas territories yesterday.
The first French territory to vote was Saint-Pierre-et-Miquelon, an archipelago near Newfoundland.