Why is there blue smoke from Renault Premium 450dxi year 2007?
It is not - turbo or cat.

Blue smoke forms when the engine's lubricating oil is being burned, indicating worn piston rings, valve guides, or valve seals. Also, the oil can come from an air filter overfilled with oil or an overfilled crankcase. If it smokes at start-up or take-off, suspect the valve seals. If it smokes all the time, the rings are likely bad.