The French government on Saturday hit back at a suggestion from US President Donald Trump that looser gun laws might have led to a different outcome to deadly attacks in Paris in 2015, in a speech in which he mimicked how the victims were shot.

Speaking to the National Rifle Association (NRA) on Friday, Trump used his hands in a gesture to act out the shooting of the Paris victims, and said if civilians had been armed "it would have been a whole different story."

"France expresses its firm disapproval of President Trump's comments about the Paris attacks on November 13, 2015 and demands that the memory of the victims be respected," the foreign office said in a statement.

"Every country freely decides on its own laws on carrying firearms, as in other areas. France is proud to be a country where acquiring and carrying firearms is strictly regulated."

That marks Paris's strongest criticism of the US president since his French counterpart Emmanuel Macron took office a year ago.

Macron - fresh from an upbeat state visit to Washington - has been trying to forge a strong relationship with the United States while tackling Trump over issues including climate change and the Iran nuclear pact.

Trump referred to Macron as a "great guy" on Friday before pointing to France as an example of a country with tough gun laws.

"No-one has guns in Paris," Trump said, adding that the Paris victims were killed by "a small group of terrorists."

He referred specifically to an attack by Islamist militants at the Bataclan concert hall, where 90 of the 130 victims of the Paris bomb and shooting rampage died.

"If one employee, or just one patron had a gun, or if one person in this room had been there with gun, aimed at the opposite direction, the terrorists would have fled or been shot," Trump said.

Former French president Francois Hollande, who was head of state at the time, said on Twitter that Trump's comments were "shameful" and "obscene".