A method for manufacturing a composite assembly comprising a rear fuselage section and a vertical tail plane of an aircraft manufactured in one shot with a continuous skin comprising two sub-structure skin halves (610, 620) the method comprising: obtaining first and second parts of a sub-structure, for each part: - obtaining a plurality of stringers preforms by composite tooling; - obtaining a plurality of frames (640, 645) preforms by composite tooling; - transferring the plurality of frames (640, 645) to curing frames moulds; and - obtaining a sub-structure skin halve (610, 620) by composite tooling; integrating the first and second parts over an integration tool comprising cavities for locating the curing frames moulds and the stringers preforms by: - positioning the curing frames moulds and the transferred frames (640, 645) preforms in the cavities for locating the curing frames moulds; - locating the stringers preforms in the cavities for locating the stringers preforms; and - laying-up the sub-structure skin halves (610, 620); - co-curing the integration tool in one shot on an autoclave; - demoulding the sub-structure skin halves (610, 620) to obtain a continuous skin; - disassembling the curing frame moulds to obtain first and second co-cured parts; and - joining the first and second co-cured parts to obtain the composite assembly of the rear section. obtaining first and second parts of a sub-structure, for each part: - obtaining a plurality of stringers preforms by composite tooling; - obtaining a plurality of frames (640, 645) preforms by composite tooling; - transferring the plurality of frames (640, 645) to curing frames moulds; and - obtaining a sub-structure skin halve (610, 620) by composite tooling; - obtaining a plurality of stringers preforms by composite tooling; - obtaining a plurality of frames (640, 645) preforms by composite tooling; - transferring the plurality of frames (640, 645) to curing frames moulds; and - obtaining a sub-structure skin halve (610, 620) by composite tooling; integrating the first and second parts over an integration tool comprising cavities for locating the curing frames moulds and the stringers preforms by: - positioning the curing frames moulds and the transferred frames (640, 645) preforms in the cavities for locating the curing frames moulds; - locating the stringers preforms in the cavities for locating the stringers preforms; and - laying-up the sub-structure skin halves (610, 620); - co-curing the integration tool in one shot on an autoclave; - demoulding the sub-structure skin halves (610, 620) to obtain a continuous skin; - disassembling the curing frame moulds to obtain first and second co-cured parts; and - joining the first and second co-cured parts to obtain the composite assembly of the rear section. - positioning the curing frames moulds and the transferred frames (640, 645) preforms in the cavities for locating the curing frames moulds; - locating the stringers preforms in the cavities for locating the stringers preforms; and - laying-up the sub-structure skin halves (610, 620); - co-curing the integration tool in one shot on an autoclave; - demoulding the sub-structure skin halves (610, 620) to obtain a continuous skin; - disassembling the curing frame moulds to obtain first and second co-cured parts; and - joining the first and second co-cured parts to obtain the composite assembly of the rear section.