Unfortunately it is not possible to start new game in Assassin’s Creed Unity. You may want to start new game because of many glitches on the game launch. Many people unlocked chests, but content disappeared and chests disappeared, missions cannot be finished, want to start new game to record Let’s Play, etc.
The only one way to start new game so far is to go to PS4 Settings, System Storage management, Application Saved data, AC Unity and delete all saved data and profile using Options key.
Assassin’s Creed Unity walkthrough. Assassin’s Creed Unity gameplay. AC Unity walkthrough. AC Unity gameplay. Assassin’s Creed Unity tips and tricks. Assassin’s Creed Unity tutorial.
Have a nice game!