Denzel Washington appeared to get heated with a photographer at Cannes Film Festival … and he could be seen warning the aggressive guy on the red carpet to shape up.

The super tense exchange occurred Monday while the Hollywood superstar attended the world premiere for his latest film — Spike Lee‘s “Highest 2 Lowest.”

It’s clear from the back and forth that the photog did something to piss DW off … which all culminated when the guy appeared to grab Denzel’s elbow, which really seemed to infuriate the actor.

Worth noting, this isn’t the first time DW has told a photog to act right … checking a group of paparazzi outside NYC’s Museum of Modern Art last October.

Still, it’s a good bet Denzel’s mood quickly shifted on Sunday … as shortly thereafter, the Oscar-winner was surprised with an honorary Palme d’Or honor before the film’s premiere.

A source with knowledge tells TMZ … Denzel is already on his way back to NYC to get ready for another sold-out showing of his ultra-popular Broadway run of “Othello.”