A motor vehicle comprising: - a passenger compartment; - two longitudinal members comprising respective rear portions arranged longitudinally in the area of said passenger compartment and respective struts, which project forward relative to said passenger compartment; - a cross member having front connection points and rear connection points; - a powertrain, which is supported by said cross member and/or by said struts; - connection members, which connect said front connection points to said longitudinal members, so as to keep said cross member suspended relative to said struts, and comprise respective breakable areas, which are designed so as to break when a given load threshold is exceeded; - connection devices, which connect said rear connection points to said rear portions; said connection devices comprising respective weakened areas designed to break so as to completely uncouple said cross member from said longitudinal members when a given load threshold is exceeded; characterized in that said rear portions comprise respective connection walls having respective first holes; said connection devices comprising: - respective plates (38,39), which are fixed relative to said connection walls and have respective second holes (44,50) vertically aligned with said first holes; - respective first connection elements, which are coupled to said plates (38,39) through welds at said second holes (44,50); - respective second connection elements, which fix said rear connection points to said first connection elements; said weakened areas being part of said plates (38,39) and/or of said welds. - a passenger compartment; - two longitudinal members comprising respective rear portions arranged longitudinally in the area of said passenger compartment and respective struts, which project forward relative to said passenger compartment; - a cross member having front connection points and rear connection points; - a powertrain, which is supported by said cross member and/or by said struts; - connection members, which connect said front connection points to said longitudinal members, so as to keep said cross member suspended relative to said struts, and comprise respective breakable areas, which are designed so as to break when a given load threshold is exceeded; - connection devices, which connect said rear connection points to said rear portions; said connection devices comprising respective weakened areas designed to break so as to completely uncouple said cross member from said longitudinal members when a given load threshold is exceeded; characterized in that said rear portions comprise respective connection walls having respective first holes; said connection devices comprising: - respective plates (38,39), which are fixed relative to said connection walls and have respective second holes (44,50) vertically aligned with said first holes; - respective first connection elements, which are coupled to said plates (38,39) through welds at said second holes (44,50); - respective second connection elements, which fix said rear connection points to said first connection elements; - respective plates (38,39), which are fixed relative to said connection walls and have respective second holes (44,50) vertically aligned with said first holes; - respective first connection elements, which are coupled to said plates (38,39) through welds at said second holes (44,50); - respective second connection elements, which fix said rear connection points to said first connection elements; said weakened areas being part of said plates (38,39) and/or of said welds.