A method for manufacturing a structural part including at least two wings extending in intersecting planes made of thermoplastic fiber-reinforced composite material including at least two plies of continuous fibers. The fibers extend from one wing to another. The method includes cutting the at least two plies in a fabric and/or a tape of fibers pre-impregnated with a thermoplastic resin; assembling the plies to create a preform; and compacting the preform to a final shape of the part by subjecting the preform to a defined cycle of temperature and pressure. A toolset can implement the method described above. Such a toolset includes a rigid punch and die such that closing the tool creates a sealed chamber in a shape of the part between the punch and the die.