Bella Hadid and longtime friend Fai Khadra had a heated argument during Paris Fashion Week

Bella Hadid may have had a falling out with one of her longtime friends at Paris Fashion Week this month … ’cause eyewitnesses say the two got into an intense verbal argument — and, they didn’t leave on speaking terms.

The argument allegedly went down at a Yves Saint Laurent after-party on Tuesday, March 11 … and, eyewitnesses tell TMZ Bella was repeatedly asking Fai Khadra to leave her alone throughout the night.

We’re told Fai refused to do so and acted inappropriately toward her … verbally berating her and raising his hands over her in an aggressive manner.

While it never got physical, our sources say it was not a friendly situation … and, Fai verbally harassed her. People say Bella looked uncomfortable, and the two didn’t leave on speaking terms.

Cops weren’t called … but, several party guests complained about Fai’s behavior to top executives at YSL.

If you don’t know Fai … he’s an artist and influencer with more than two million followers on Instagram. He’s a close personal friend to Hailey Bieber, Kendall and Kylie Jenner, too — but, despite speculation, he’s never been romantically involved with these ladies.