Method for manufacturing a covering panel made of plastic, having two pairs of parallel sides, to be assembled by its pairs of sides to other panels of the same type whose pairs of sides have complementary assembly profiles, a top and a bottom, the sides of the panels being assembled along junction planes, each panel having: one pair of sides for assembly by pivoting the side of one panel into the homologous side of another already placed panel, and another pair of transverse sides (1, 2) for assembly by nesting of shapes and clip-fastening by this movement into the homologous transverse side of another already placed panel, a first transverse side having a junction plane at the edge of the top of the panel is extended by a locking cavity opening towards the top and by a hook, the second transverse side, which is homologous to the first side, having an upper edge in the junction plane terminating a projection and separated from the body of the panel by an assembly cavity of one panel covering the hook of another panel and the projection being housed in the cavity of this other panel, which method is characterized in that - the blank of the pair of transverse sides (1, 2) is formed by giving the first side its final cross section and by producing, on the second side, an assembly cavity opening into the bottom of the profile and a projection provided with a tip arriving in the junction plane and followed by a clearance set back from the junction plane and whose bottom wall is extended by a tab projecting from the base of the projection, - the zone of the base of the tab is heated locally, - then, when this zone is softened, the tab is lifted in the direction of the clearance to form the latch, and - the shape is stabilized by cooling it to obtain the panel whose two transverse sides (1, 2) have their final shape. each panel having: one pair of sides for assembly by pivoting the side of one panel into the homologous side of another already placed panel, and another pair of transverse sides (1, 2) for assembly by nesting of shapes and clip-fastening by this movement into the homologous transverse side of another already placed panel, one pair of sides for assembly by pivoting the side of one panel into the homologous side of another already placed panel, and another pair of transverse sides (1, 2) for assembly by nesting of shapes and clip-fastening by this movement into the homologous transverse side of another already placed panel, a first transverse side having a junction plane at the edge of the top of the panel is extended by a locking cavity opening towards the top and by a hook, the second transverse side, which is homologous to the first side, having an upper edge in the junction plane terminating a projection and separated from the body of the panel by an assembly cavity of one panel covering the hook of another panel and the projection being housed in the cavity of this other panel, which method is characterized in that - the blank of the pair of transverse sides (1, 2) is formed by giving the first side its final cross section and by producing, on the second side, an assembly cavity opening into the bottom of the profile and a projection provided with a tip arriving in the junction plane and followed by a clearance set back from the junction plane and whose bottom wall is extended by a tab projecting from the base of the projection, - the zone of the base of the tab is heated locally, - then, when this zone is softened, the tab is lifted in the direction of the clearance to form the latch, and - the shape is stabilized by cooling it to obtain the panel whose two transverse sides (1, 2) have their final shape. - the blank of the pair of transverse sides (1, 2) is formed by giving the first side its final cross section and by producing, on the second side, an assembly cavity opening into the bottom of the profile and a projection provided with a tip arriving in the junction plane and followed by a clearance set back from the junction plane and whose bottom wall is extended by a tab projecting from the base of the projection, - the zone of the base of the tab is heated locally, - then, when this zone is softened, the tab is lifted in the direction of the clearance to form the latch, and - the shape is stabilized by cooling it to obtain the panel whose two transverse sides (1, 2) have their final shape.