He mimicked gunmen summoning and shooting victims one by one, saying "Boom! Come over here!" and using his hand to imitate a gun being fired.
In reality, the attackers sprayed many of their 130 victims with semi-automatic fire and set off bomb belts.
The French foreign ministry called for the victims' memory to be respected.
"France expresses its firm disapproval of the comments by President Trump about the attacks of 13 November 2015 in Paris and asks for the memory of the victims to be respected," the foreign ministry said.
Paris attacks: What happened on the night
François Hollande, who was French president at the time of the attacks, said Mr Trump's remarks were "shameful". They "said a lot about what he thinks of France and its values", he added.
Manuel Valls, who was France's prime minister in 2015, tweeted: "Indecent and incompetent. What more can I say?"
In the same speech to the National Rifle Association (NRA) in Dallas, Texas, the US president criticised the level of knife crime in London, comparing one of the city's hospitals to a "war zone".
A senior London surgeon, Prof Karim Brohi, hit back by saying it was "ridiculous" to suggest guns could help combat knife violence.
What did Trump say exactly?
"Paris, France, has the toughest gun laws in the world..." he told the NRA.
"Nobody has guns in Paris, nobody, and we all remember more than 130 people, plus tremendous numbers of people that were horribly, horribly wounded. Did you notice that nobody ever talks about them?
"They were brutally killed by a small group of terrorists that had guns. They took their time and gunned them down one by one. Boom! Come over here. Boom! Come over here. Boom!
"But if one employee or just one patron had a gun, or if just one person in this room had been there with a gun, aimed at the opposite direction, the terrorists would have fled or been shot."
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