Rihanna and Chris Brown: Fighting Over Karrueche Tran!

Rihanna and Chris Brown are reportedly at odds again, and Karrueche Tran is to blame.

The Human Pantsless Instagram Photo Factory is angry with her man after he partied with his model ex after his Paris gig on Friday night, The Sun (UK) reports.

“She can’t get it into her head that Chris will never change," a source told the tabloid.

“She’s given him so many chances since he beat her up and he still keeps hurting her. Letting Karrueche meet him is yet another blow for Rihanna that will further disgust her fans."

"They are already raging that she is back with him.”

Karrueche Tran jetted off to Paris with her brand-partner stylist for The Kill, Ugo Mozie, on Friday. Mozie also styles Chris Brown, who dated Tran for over a year.

Tran reportedly plans to then follow the "Don't Wake Me Up" singer to the Dubai leg of his "Carpe Diem" tour, The Sun reports, and Rihanna is fed up.

She was going to stay with Chris in Paris, but reportedly headed straight to Manchester (UK) to perform on the X Factor final’s results show, the source added.

Rihanna allegedly sent out a series of angry tweets:

• "Examine what you tolerate."
• "Goodbye muthaf**ker."
• "You give, you get, then you give it the f**k back."

These tweets appear to have been deleted, however, and all may have been forgiven, as Rihanna later tweeted about missing her man. So ... that's that?

Reports of Rihanna-Chris discord come after she got a Breezy tattoo in his honor, and after posing photos of him in bed, and embracing her, and so on.

"She got it to symbolize her commitment to him. Now the whole world knows they’re back together, they’re determined to make it work," a source said.

Until he feels like nailing his ex, apparently.

The real question: Who'd you rather ...