The veteran director was spotted hanging out solo Saturday on Nikki Beach in the South of France, where he was enjoying the final day of the festival after debuting his newest flick, "Once Upon a Time in Hollywood," a few days earlier.

Eyewitnesses say Tarantino was minding his business while he sucked down the stogie. We're told he had a glass in his hand too, but it's unclear if or what he might've been drinking. More importantly, he looks totally relaxed despite a testy exchange he got into Wednesday.

After the 'OUATIH' screening, QT and the rest of the main cast -- including Brad Pitt and Leonardo DiCaprio -- hit the podium to answer questions from the media. One reporter noted Margot Robbie's character -- Sharon Tate -- didn't have very many lines throughout the film, and asked why that came to be.

Quentin answered curtly, "Well, I just reject your hypotheses" ... and didn't elaborate any further. Margot did though, saying she thought she was able to accurately capture Sharon's essence without much dialogue ... and was happy with the challenge of doing so.

It's interesting ... Quentin was widely characterized as having "snapped" at the reporter who asked the tough question, but it doesn't look like he's sweating it one bit days later.