The cancelled project is said to be connected to the Japanese arm of Square Enix, and was reported to have been a new IP.
Earlier this week, Lightning Returns: Final Fantasy XIII game director Yuji Abe said that the company has discussed Eidos working on a Final Fantasy game. "That's certainly been discussed within the company, the possibility of say, Eidos or maybe someone else to look after or maybe take on the Final Fantasy series," he said.
In 2008, Swedish developer Grin began preproduction work on a Final Fantasy spin-off game called Fortress. The game was cancelled six months into development.
Eidos Montreal's next game, Thief, will be released for the Xbox One, PlayStation 4, PC, Xbox 360, and PlayStation 3 in February 2014. The Deus Ex: Human Revolution Director's Cut was released last week.