Cannes, France - Hollywood star Robert De Niro slammed President Donald Trump as a "philistine" Tuesday as he accepted a lifetime achievement award at the Cannes film festival.

The 81-year-old actor said that "in my country we are fighting like hell for the democracy we once took for granted" against "America's philistine president".

De Niro, a fierce and longtime critic of his fellow New Yorker Trump, said the president's swingeing cuts in funding for the arts and education were deliberate.

"Because art is the crucible that brings people together... Art looks for truth. Art embraces diversity. That's why art is a threat. That's why we are a threat to autocrats and fascists."

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The Taxi Driver and Goodfellas star lambasted Trump for threatening tariffs on movies "produced in foreign lands".

"And now he has announced 100% tariffs on film production outside of America. You can't put a price on creativity. But apparently, you can put a tariff on it. Of course, all these attacks are unacceptable. This is not just an American problem, it is a global one," he added.

"We can't just all sit back and watch. We have to act, and we have to act now," he urged.

The Hollywood legend cried as his friend Leonardo DiCaprio presented him with his honorary Palme d'Or prize.

DiCaprio thanked De Niro for recommending him to Martin Scorsese, who has since made six films with the star, from Gangs of New York to Killers of the Flower Moon.