The France international sealed a season-long loan switch to Hull City from Newcastle United at the end of the previous transfer window, after falling out of favour at St James' Park.
However, the 27-year-old made just five Premier League starts under Steve Bruce, who last month declared that he did not know the whereabouts of the player.
Bruce went on to say that Ben Arfa had played his last game for the club, before full-time employers Newcastle terminated his contract by mutual consent ahead of a proposed switch to Nice.
That move has since gone through, and Ben Arfa - who made his professional debut against Nice for Lyon - was delighted to have joined up with Claude Puel's men.
"Nice are a club with a big identity," he said. "In 10 minutes, my choice was made.
"Even if Real Madrid had come, I said yes to Nice. I want to have fun.
"Claude Puel is a person of integrity, with true human values. His speech I liked immediately.
"Nice will be the perfect place to grow. They have a history. This club built something. Its leaders are ambitions. It is very good for me.
"Me, a genius? It comes from journalists. I'm just a player looking to work and have fun."
Nice, who sit 11th in Ligue 1, host Lorient on Saturday.
