Fabric roller blind, which comprises: - a support frame intended to be fixed to a load-bearing element in which an opening is made; - a take-up roller rotatably constrained to said support frame, having a substantially horizontal rotation axis, and intended to be positioned above said opening; - two lateral guideways extended parallel to one other and side-by-side each other along respective first extension directions substantially orthogonal to the rotation axis of said take-up roller, and intended to be fixed to said load-bearing element along respective sides of said opening; - a fabric extended between an upper edge thereof fixed to said take-up roller and a lower edge thereof, and susceptible of sliding between said lateral guideways; - a bottom bar, to which the lower edge of said fabric is fixed and which is extended, along a second extension direction parallel to the rotation axis of said take-up roller, between two lateral ends thereof slidably engaged with the corresponding lateral guideways; - movement means mechanically connected to said take-up roller and adapted to rotate said take-up roller so as to move said fabric between a retracted position, in which said fabric is wound around said take-up roller, and an extended position, in which said fabric is at least partially unwound from said take-up roller extended between said lateral guideways to cover at least part of said opening; - at least one guide body, which is mechanically associated with a lateral end of said bottom bar and is provided with a shaped track, intercepted by at least one locking element and provided with at least one inlet opening and with at least one outlet opening; - at least one oscillating rotor, placed at the lower end of at least one said lateral guideway, is provided with a slider element susceptible of sliding in a guided manner within the shaped track of the guide body of the lateral end of said bottom bar in order to be engaged with and disengaged from said locking element and consequently retaining and releasing said bottom bar; said blind being characterized in that said shaped track is provided with one or more steps descending in the travel direction from said inlet opening to said outlet opening and in that the slider element of said oscillating rotor is susceptible of sliding on the bottom of said shaped track in said travel direction, overcoming said one or more steps during descent. - a support frame intended to be fixed to a load-bearing element in which an opening is made; - a take-up roller rotatably constrained to said support frame, having a substantially horizontal rotation axis, and intended to be positioned above said opening; - two lateral guideways extended parallel to one other and side-by-side each other along respective first extension directions substantially orthogonal to the rotation axis of said take-up roller, and intended to be fixed to said load-bearing element along respective sides of said opening; - a fabric extended between an upper edge thereof fixed to said take-up roller and a lower edge thereof, and susceptible of sliding between said lateral guideways; - a bottom bar, to which the lower edge of said fabric is fixed and which is extended, along a second extension direction parallel to the rotation axis of said take-up roller, between two lateral ends thereof slidably engaged with the corresponding lateral guideways; - movement means mechanically connected to said take-up roller and adapted to rotate said take-up roller so as to move said fabric between a retracted position, in which said fabric is wound around said take-up roller, and an extended position, in which said fabric is at least partially unwound from said take-up roller extended between said lateral guideways to cover at least part of said opening; - at least one guide body, which is mechanically associated with a lateral end of said bottom bar and is provided with a shaped track, intercepted by at least one locking element and provided with at least one inlet opening and with at least one outlet opening; - at least one oscillating rotor, placed at the lower end of at least one said lateral guideway, is provided with a slider element susceptible of sliding in a guided manner within the shaped track of the guide body of the lateral end of said bottom bar in order to be engaged with and disengaged from said locking element and consequently retaining and releasing said bottom bar;