The film is written and directed by Glenn Ficarra and John Requa, with Denise DiNovi serving as the producer, reports Deadline.
Although Gosling and Stone are wanted for the lead roles, the studio apparently "hasn't gotten that far yet".
DiNovi was the producer for another Warner Bros film, last year's Crazy, Stupid, Love, starring Gosling, Stone, Steve Carell and Julianne Moore.
Focus follows a veteran conman who gets involved romantically with a newcomer to the grifter business.
Both Gosling and Stone are set to appear together in The Gangster Squad about the conflict between the Los Angeles Police Department and East Coast Mafia members in the 1940s and 1950s.
Watch the trailer for Crazy, Stupid, Love below: