A trimming and sealing assembly and an upper portion of a frame of a window in a door of a motor vehicle, the window having an associated transparent pane, movable between a lowered opening position and a raised closing position, said upper portion of the frame of the window including at least one longitudinal support flange, including a sheet metal member having an essentially L-shaped cross-section, with an upper wing forming an angle with respect to said pane and provided with coupling means, in the form of longitudinally spaced and downwardly protruding tabs, and with a rear lateral wing or flap turned towards the inside of the motor vehicle extending at least in part downwards; wherein the trimming and sealing assembly comprises a rigid bearing profile, having an essentially L-shaped cross-section, with an upper wing extending above the upper wing of said flange and a front lateral wing turned, in use, towards the environment outside the motor vehicle and facing the rear lateral wing of said flange, such that between the support flange and the bearing profile there is defined a downwardly-open seat; to the front wing of the bearing profile there being connected an external trimming profile; in said seat there being mounted a sealing strip having an essentially inverted U-shaped cross-section, with first and second lateral branches (21a, 21b), which are adjacent the front wing of the bearing profile and to the rear wing of the support flange, respectively, and provided with respective longitudinal sealing lips (21d, 21e) adapted to contact the opposite surfaces or faces (5a, 5b) of said transparent pane when the latter is in said closed position; in the bearing profile there being defined an upper longitudinal space, which extends adjacent said seat and in which said support flange extends; and a plurality of anchoring clips having an essentially C- or U-shaped cross-section, predisposed in longitudinally-spaced positions in the upper space of the bearing profile and retained therein by said coupling means, each anchoring clip having an upper branch and a lower branch, opposite one another and able to be resiliently divaricated and between which there is fitted with interference and snap-engaged said support flange. said upper portion of the frame of the window including at least one longitudinal support flange, including a sheet metal member having an essentially L-shaped cross-section, with an upper wing forming an angle with respect to said pane and provided with coupling means, in the form of longitudinally spaced and downwardly protruding tabs, and with a rear lateral wing or flap turned towards the inside of the motor vehicle extending at least in part downwards; wherein the trimming and sealing assembly comprises a rigid bearing profile, having an essentially L-shaped cross-section, with an upper wing extending above the upper wing of said flange and a front lateral wing turned, in use, towards the environment outside the motor vehicle and facing the rear lateral wing of said flange, such that between the support flange and the bearing profile there is defined a downwardly-open seat; to the front wing of the bearing profile there being connected an external trimming profile; in said seat there being mounted a sealing strip having an essentially inverted U-shaped cross-section, with first and second lateral branches (21a, 21b), which are adjacent the front wing of the bearing profile and to the rear wing of the support flange, respectively, and provided with respective longitudinal sealing lips (21d, 21e) adapted to contact the opposite surfaces or faces (5a, 5b) of said transparent pane when the latter is in said closed position; in the bearing profile there being defined an upper longitudinal space, which extends adjacent said seat and in which said support flange extends; and a plurality of anchoring clips having an essentially C- or U-shaped cross-section, predisposed in longitudinally-spaced positions in the upper space of the bearing profile and retained therein by said coupling means, each anchoring clip having an upper branch and a lower branch, opposite one another and able to be resiliently divaricated and between which there is fitted with interference and snap-engaged said support flange.