You connect it with a USB.  Change the ps3 controller to #2. Turn on the ps4 controller and voila it works.  

Not sure if this was known.  But it's cool being able to use the DS4 when playing the ps3.

It's known, but last I checked the PS button didn't work.

Yeah I'm sure we knew this before, well at least I did.

Only annoyance is that the vibration doesn't work, and the PS Button doesn't work.

I think I prefer the DS3.

I prefer the DS4, and I was a huge fan of the DS3.

I'm old-fashioned: DS4 looks too different from the DS1-2-3. Just my two cents.

I liked the DS3 but after getting used to thr DS4 my hands hurt sometimes when going back to the DS3. 

Anyway I see this was known already.  I think it's really neat.  And yeah the ps button doesn't work 

Yeah, I've resisted playing some of my legacy PS3 games because it's hard to go back to DS3. It is a lot smaller, and on my DS3's the analog sticks are really loose and don;t feel like they control the game as tightly as the DS4 sticks.

And of course L2 and R2 are way better on DS4.

Could Sony do a firmware to have DS4 work natively on PS3? I guess they figure it's not worth the time and effort.

I used this a lot when PS4 came out. I actually had the DS4 a couple of weeksahead of the PS4. I have been using it for PS3 and PC ever since.

Just use this trick instead.  It does the job