Seat assembly and vehicle comprising such seat assembly

A rear seat assembly of a vehicle, said rear seat assembly comprising a first seat and a backrest interposed between an internal space and a trunk of said vehicle, said rear seat assembly comprising a second seat suitable for transporting children, said second seat is carried by said rear seat assembly, said assembly of rear seat is configured to assume a first configuration in which said second seat is housed inside said trunk and said first seat and said backrest are free to use and a second configuration in which said backrest is moved to allow said second seat to come out of said trunk and to use it for transporting a child, wherein said second seat is carried by said backrest, said first seat is configured to tip over with respect to a front edge, shifting from a first closed configuration to a second open configuration, in which it touches an element of said vehicle, and said backrest is configured to slide with respect to and tilt with respect to a bottom of said vehicle in order to shift from a first retracted configuration to a second open and overturned configuration, in which it is in contact with said element and locked to rotation, said second seat facing away from said element.