12:30PM BST 09 Aug 2011
Obertan, whose first team chances with United were limited during his two years with them, is relishing the prospect of regular football with Newcastle.
"I have come here with a lot of ambition," he said. "I just want to play football."
Newcastle manager Alan Pardew was delighted to have landed a long-term transfer target.
He said: "It's good news for us. He is a player we have been after for some time.
"With Wayne Routledge moving on there was an opportunity to bring him in.