Is there no Assassins Creed Unity for Playstation 3?

Unfortunately, only find the https://www.rebuy.de/kaufen/suchen?q=Assassins%20Creed%20Unity%20PS3, on Amazon, for example, I find nothing just as few at Ubisoft.

How can that be, where can you still buy it?

The game never came out for the PS3 only for the PS4

Unity was technically not feasible on the PS3. Simultaneously with Unity came out on the PS3 AC Rogue. Good game.

I'm currently playing AC Rogue, but I still don't understand one thing, why does Rebuy offer this for the PS 3?

Do not understand your question ;-). There's Rogue as written for PS3 (meanwhile also for PS4). Unity is not available for PS3.

If rebuy offers AC Unity for PS3 it is wrong.