US President Donald Trump and Russian President Vladimir Putin have met for the first time since the Helsinki summit in July.

The pair are in Paris, France, to mark 100 years since the armistice that ended World War I.

Putin exchanged brief handshakes with other world leaders, but he and Trump engaged in mutual arm and back patting.

During the event, French President Emmanuel Macron issued a strong rebuke of nationalism.

US President Donald Trump and his Russian counterpart Vladimir Putin have met for the first time since the Helsinki summit in July.

The pair are in Paris, France, to mark 100 years since the armistice that ended World War I. They observed a commemoration ceremony alongside other world leaders at the Arc de Triomphe.

Read more: A topless protester got dangerously close to Donald Trump's motorcade in Paris

Putin arrived later than Trump, French President Emmanuel Macron, and German Chancellor Angela Merkel, greeting all three leaders consecutively.

While Putin's handshakes with Macron and Merkel were brief, he and Trump engaged in mutual arm and back patting. He also flashed Trump a thumbs up, which is something of a signature move of the US president during photo-ops.

You can watch the exchange below:

It is their first meeting since the Helsinki summit, where the pair held closed-door talks and a joint press conference.

During that press conference, Trump said he saw no reason to believe Russia had interfered in the 2016 US election, but was later forced to walk back the remarks.

First lady Melania Trump greeted Putin, as well. Reuters

Others noted that Trump smiled warmly at Putin, while Macron and Merkel greeted the Russian president with a more stony expression.

Elsewhere during the Armistice Day event on Sunday, Macron rebuked nationalism in what could be read as a direct attack on Trump's "America First" agenda. The French president said:

"Nationalism is a betrayal of patriotism. By saying our interests first, who cares about the others, we erase what a nation holds dearest, what gives it life, what makes it great and what is essential: its moral values.

"I know there are old demons which are coming back to the surface. They are ready to wreak chaos and death... History sometimes threatens to take its sinister course once again."