The tweet was a negative reference to the "Je Suis Charlie" (I am Charlie) hashtag that became a popular way of showing solidarity in the wake of this month's Islamist attack on Paris magazine Charlie Hebdo that left 12 people dead.
The Syrian Electronic Army (SEA) also managed to tweet in support of Palestine and against the bombing of Syria before the account was suspended.
Le Monde's account was back up Wednesday morning with a tweet reading: "Our account was hacked, but we have it back under control. We apologise for the fake messages posted in our name."
The paper said Tuesday that the group had tried and failed to hack its website on Sunday and Monday. The hackers had attempted to get into its Twitter account by sending false emails to its editors.
SEA aims to spread counter-revolutionary propaganda and hit back at news outlets it says slant their reporting of the Syria conflict.
Their most notorious hack was of The Associated Press's Twitter stream, resulting in a false tweet saying President Barack Obama had been injured after two blasts at the White House. The message saw the Dow Jones Industrial Average suffer a "flash crash" before traders realised the tweet was false.
Other victims of SEA hacks include the AFP photo department's Twitter account, the BBC, Al Jazeera, the Financial Times and the Guardian.