"Restitution" is usually used to indicate some kind of financial or other compensation, not simply the return of stolen property.
I would avoid "restoration" in this context because if you talk about restoration of museum artefacts, people are likely to think you mean repair, cleaning, recolouring, etc, of the the items, NOT their return to the rightful owners.
Sorry to disagree, but restitution has two meanings - one to do with financial compensation and the other to do with the return of stolen property, so it is entirely appropriate here. But please could you give us an example sentence, maayani - sometimes the immediate context makes a big difference to what is idiomatic.
Here is how the return occurred:
At the time of the theft of the Mona Lisa, the newspapers announced that a reward would be given to the person who brought back the picture. There was a promise not to inform against him.
Then a stranger offered to “Paris Journal” not the Mona Lisa, but a statuette stolen from the Louvre ...