Hollande was referring to Trump's recent comments about captain Humayun Khan, a US Muslim soldier killed in Iraq in 2004.
Donald Trump has hit back at Barack Obama for terming him unfit for presidency, saying the "terrible president" would go down as the worst in American history.
The Islamic State on Sunday condemned a US Muslim soldier killed in Iraq, whose story has re-ignited debate in the 2016 presidential election on the role of Muslims in American life, as an apostate
Trump's remarks gathered storm as some Republicans also rounded on their candidate.
Donald Trump rejected criticism from the father of a soldier killed in Iraq who said the Republican presidential nominee had "sacrificed nothing and no one" and questioned whether the mother was allowed to speak during the couple's appearance at the Democratic convention.