The most fearful examples of misinformation come from the darker corners of the Internet, but many found a wider audience in social media.
InfoWars, a fringe site known to propagate conspiracy theories, published a story suggesting that the fire had been deliberately discontinued. The InfoWars story stays online.
"Nothing shows that this is a deliberate act," he said in a press conference on Tuesday.
However, some social media users made allegations that went beyond the statements asserted by InfoWars. On Twitter, a fake account operated like one by CNN claims that the fire was caused by terrorism.
The account created in April was removed just hours after CNN publicly called Twitter.
Conspiracy theories about the emergence of fire were also abundant on the 4chan Internet scoreboard, where users used trolling tactics that were intended to aggravate the media.
High-profile social media users pushed conspiracy theories forward, and some attempted to blame racial or religious minorities for the outbreak of the fire.
One strategy appeared to be the use of old and independent articles on Catholic churches desecrated in France to suggest that the Notre Dame fire was a deliberate act.
. Other reports published a flawed 2016 article about tanks and "Arab documents" near the cathedral.
Big social media companies have apparently struggled to stem the spread of content.
Donie O & Sullivan of CNN contributed to this report.