The invention provides an aircraft fuselage (10) comprising a pressurized cabin (13) and an unpressurized rear section (15) separated by a rear pressure bulkhead (12) that comprises flat portions forming one or more kinks between them, one of said kinks being contiguous to the rear border (19) of the floor (17) that divides the space of the pressurized cabin (13) into upper and lower compartments (21, 23).