"However, there are some limitations when using the DualShock 4 on the PlayStation 3. These are:
No Rumble Feedback (Vibration)
Motion Sensing does not work
Touch Pad does not work
PS Button does not work
Speaker on DualShock 4 does not work
Headset port does not work
Light bar has no effect on the game, as it just stays a whiteish, blue colour (when used wireless)"
Games that aren't compatible with DS4 on PS3:
Armored Core 4 (Works for user interface navigation but offers no control during combat)
Armored Core for Answer (Same as Armored Core 4)
Batman: Arkham Origins Blackgate - Deluxe Edition
Bloodrayne: Betrayal (Only detects Start button and Analogic)
Burnout Crash
Castlevania Lords of Shadows
Disney Universe
Ducktales Remastered (Only detects Start button and Analogic)
Gran Turismo 5 (Works for user interface navigation but offers no control during races)
Gran Turismo 6
Jak and Daxter Collection (Only detects Start button and Analogic)
LA Noire (Works for all gameplay except driving segments)
Metal Gear Solid 2 HD
Metal Gear Solid 3 HD
Minecraft Playstation 3 edition
Ratchet & Clank: All 4 One
Ratchet & Clank: Full Frontal Assault
Ratchet & Clank: Into the Nexus
Resistance 3
Resonance of Fate (everything works except for the left analog stick which is necessary)
Saints Row: The Third
Saints Row IV (Analog sticks only work, buttons don't)
Tears to Tiara II : Heir of the Overlord
Telltale's "The Wolf Among Us"
Tom Clancy´s Splinter Cell HD Trilogy (Makes sense, actually. Since you need the rumble to lock pick on doors).