The invention discloses signaling assembly (2, 3, 4) for a door leaf (60, 70) of an access door (50) to a transport vehicle, in particular a rail vehicle, said door leaf comprising a body and a profile (1, 1') extending over at least one portion of the periphery of this body, said profile defining a housing (14) open opposite said body, said signaling assembly comprising a seal (2), said seal comprises an attaching region (21), intended to be received at least partially in said housing of said profile, as well as a lighting region (20), means of lighting (4), able to illuminate said lighting region of said seal, in such a way as to emit at least one visual signal, in particular representative of the opened and/or closed state of the door, characterized in that: said assembly further comprises at least one locking key (3) received at least partially in an interior volume (28) of said seal, said key being able to prevent a pulling off of said seal outside of said profile along a transversal direction (Y1-Y1), in reference to the main direction of said seal, the means of lighting (4) being fixed on said locking key.