A roller screen , in particular in the form of an insect net or the like, for shielding a building aperture , in particular a roof window area, in an inclined wall, which roller screen comprises: a top casing defining a first longitudinal direction and in which a spring-biased roller bar is arranged rotatably, a bottom bar configured to extend substantially in parallel with the top casing and being manually operable, a first side rail and a second side rail , each extending in a second longitudinal direction, substantially perpendicular from a respective end of the top casing , a screening body having two side edges and a predefined length between a first end portion connected to the roller bar and a second end portion connected to the bottom bar , said screening body being movable in the second longitudinal direction between a non-screening position and a screening position in which the screening body is unwound from the roller bar and covers the building aperture, the two side edges of the screening body being preferably provided with discrete or continuously positioned thickenings guided in a first track wherein the bottom bar comprises a longitudinal groove and at least one insert element (20; 201, 202; 203) accommodated within the longitudinal groove , characterised in that said preferably provided discrete or continuously positioned thickenings have a transverse dimension larger than an opening of said first track, and the at least one or more insert element (20; 201, 202; 203) delimits a handle portion within the longitudinal groove to allow a user to introduce finger/s into the longitudinal groove for gripping the bottom bar at a central section of the bottom bar . a top casing defining a first longitudinal direction and in which a spring-biased roller bar is arranged rotatably, a bottom bar configured to extend substantially in parallel with the top casing and being manually operable, a first side rail and a second side rail , each extending in a second longitudinal direction, substantially perpendicular from a respective end of the top casing , a screening body having two side edges and a predefined length between a first end portion connected to the roller bar and a second end portion connected to the bottom bar , said screening body being movable in the second longitudinal direction between a non-screening position and a screening position in which the screening body is unwound from the roller bar and covers the building aperture, the two side edges of the screening body being preferably provided with discrete or continuously positioned thickenings guided in a first track wherein the bottom bar comprises a longitudinal groove and at least one insert element (20; 201, 202; 203) accommodated within the longitudinal groove , characterised in that said preferably provided discrete or continuously positioned thickenings have a transverse dimension larger than an opening of said first track, and the at least one or more insert element (20; 201, 202; 203) delimits a handle portion within the longitudinal groove to allow a user to introduce finger/s into the longitudinal groove for gripping the bottom bar at a central section of the bottom bar . <EOS>