The fan manufacturer’s instructions for the ones I use usually only require GFCI for them when they are directly in or over the tub or shower itself. A paddle fan would be a different story. Check out NEC 410.10[D] anyway. Do you have other local requirement for this?
KJay is right, 410.10(D) is where the 3 feet comes from but that is a paddle fan.
(D) Bathtub and Shower Areas. No parts of cord-connected luminaires, chain-, cable-, or cord-suspended luminaires, lighting track, pendants, or ceiling-suspended (paddle) fans shall be located within a zone measured 900 mm (3 ft) horizontally and 2.5 m (8 ft) vertically from the top of the bathtub rim or shower stall threshold. This zone is all encompassing and includes the space directly over the tub or shower stall. Luminaires located within the actual outside dimension of the bathtub or shower to a height of 2.5 m (8 ft) vertically from the top of the bathtub rim or shower threshold shall be marked for damp locations, or marked for wet locations where subject to shower spray.