Chris Brown and Karrueche Tran's renewed “relationship” is already off to a rocky restart.

Yeah, they seemed to have a good time together at the Billboard Music Awards, but they were in a fender bender on Tuesday in L.A. when CB's Range Rover rear-ended a woman's Mercedes.

According to Gossip Cop, there were no injuries and no authorities were called to the scene ... but X17 Online's photographers took a bunch of photos and you can see Karrueche try to help by apparently taking a photo of the back of the car. Chris and the other driver exchanged information, then moved on.

No biggie, this kinda thing happens all the time in L.A., but back in February, Chris crashed his car the day before the Grammys and his rep blamed "aggressive pursuit by the paparazzi." Maybe there should be a special driving course for famous people who hate being followed (as opposed to the ones who love it — and there are plenty).

Sources: Gossip Cop, X17 Online