Chris Brown and Quavo have been at odds for years over their mutual connection to Karrueche Tran ... which is why Chris is so pissed about an awkward moment at Paris Fashion Week.

Here's the deal ... CB and Quavo were plopped right next to one another Sunday at the Rhude Menswear Fall/Winter '24 showcase -- and yes, they were definitely uncomfortable with the situation, evidenced by their body language.

The clip of them sitting there and squirming went viral, but then Chris chimed in as everyone cracked jokes about it -- he commented, "Can't pick who u sit by. F*** all that growth s***."

He added, "N**** not finna fumble my bag for little n*****." In other words, he wasn't gonna make a big stink, or start a fight, over getting placed -- seemingly by coincidence -- next to Quavo.

As he notes, there are bigger issues to worry about -- y'know, like getting paid!

In case you're unfamiliar, Quavo dated Karrueche in 2017 -- not long after CB broke things off with her, following a tumultuous relationship -- and Chris certainly didn't like it back then.

In fact, we'd been told at the time that he was fuming over this ... and felt like the Migos rapper had outright betrayed him. They've traded jabs back and forth since then -- almost coming to blows after the 2017 BET Awards.

Anyway, Chris is making a couple things clear -- yes, he still doesn't like Quavo, but also ... he's a grown-up who's able to control his emotions.

Quavo's been quiet about their Paris run-in.