The Chelsea striker returned to Inter on a straight loan yesterday.
"We signed the documents a few minutes ago, it's all done," lawyer Sebastien Ledure told Sky Italia.
“We are all very happy and also tired, but it's all OK. We're very happy with this move.
“Nobody believed at the beginning, everyone said it was impossible, so we had to be discreet and work in the shadows. It's what we did, so did Chelsea and Inter. This is the result, Big Rom is back and we already know it's going to be a success."
Ledure continued: “There was fear in every moment, because it was a very difficult situation that we'd never seen before, a player sold a year earlier for a price that we all know was going to be difficult. But we believed from the first moment, we worked step by step and that was the best way to do it."
On staying next season, he added: “We don't know. Nobody can talk about what happens a year from now. Let us enjoy this season, enjoy this comeback and then we'll see. The important thing is he is back and he's very happy. That's what matters for now."