The midfielder's move to the Allianz Riviera on a free transfer was announced last Monday after he passed a medical.
Newcastle United cancelled Ben Arfa's contract after he returned from a loan spell with Premier League rivals Hull City, in which he made only eight top-flight appearances before Steve Bruce revealed the 27-year-old had gone absent without leave.
The FFF did not give the former Marseille man clearance to make his Nice debut in a 3-1 home win over Lorient on Saturday due a FIFA rule that prevents players from turning out for three clubs in the same season.
Ben Arfa played for Newcastle's Under-21 side before turning out for Hull, but Nice argue that by not appearing for the Tyneside club's first team he should be permitted to feature for them this season.
Nice say that the Football Association have confirmed in writing that the Under-21 fixture is not classed as an official match and that statement has been passed on to FIFA.
The club now hope coach Claude Puel will be able include Ben Arfa in his squad for this week's clash at Stade Chaban-Delmas.
