Floor panel for forming a floor covering, wherein this floor panel substantially consists of synthetic material and is of the supple type; wherein by a supple panel a panel is meant, which panel, when, in the case of a rectangular panel with a width of less than 50 centimeters, it is fixedly clamped on one short side of the panel and thereby projects over a length of 100 centimeters and is not supported, bends under the influence of its own weight, wherein this bending at the height of the free extremity is minimum 10 centimeters in respect to the clamped extremity, this when taking into account a bending time of 10 seconds and starting from a flat horizontal position; wherein the floor panel, on at least one pair of opposite edges, comprises coupling parts which allow joining two of such floor panels by means of a downward movement of one floor panel in respect to the other floor panel, wherein these coupling parts allow a locking in a first direction perpendicular to the plane of the floor panels as well as in a second direction perpendicular to the respective edge and in the plane of the floor panels; wherein the coupling parts comprise a first locking system for the locking in said first direction and a second locking system for the locking in said second direction; wherein the second locking system substantially is formed of an upwardly directed lower hook-shaped part situated on an edge, as well as of a downwardly directed upper hook-shaped part situated on the opposite edge, which hook-shaped parts can be engaged behind each other by said downward movement; wherein the lower hook-shaped part consists of a lip which extends laterally from the lower edge of the panel and which is provided with an upwardly directed locking element with a locking surface, whereas the upper hook-shaped part consists of a lip which extends laterally from the upper edge of the panel and which is provided with a downwardly directed locking element with a locking surface; wherein said first locking system comprises a separate locking element; wherein said separate locking element is provided in a longitudinal recess which is present on the respective edge at a distance underneath the upper surface, more particularly the upper side, and is separated from the upper surface by a lip-shaped part; wherein this lip-shaped part, seen in cross-section, comprises a proximal end and a distal end and wherein the distal end defines an upper edge; wherein the lip-shaped part, near the proximal end, has a thickness, herein below denominated proximal thickness, wherein this proximal thickness is formed by a distance perpendicular to the upper surface, measured from the upper surface to a tangent point determined by a line at an angle of 60° with said upper surface, which is directed downward in proximal direction and which is tangential to said recess; and wherein the lip-shaped part, seen in cross-section, has a horizontal length which is formed by the horizontal distance between the most distal end of the lip-shaped part and the most proximal point of said recess; characterized in that the floor panel combines the following two features: - on the one hand, that said locking surfaces are configured such that in the coupled condition, on a location where they contact each other, they form an angle different from 90 degrees with the plane of the floor panel; - and, on the other hand, that said lip-shaped part shows at least one of the following features or a combination of any two or three of the following features, or all four of the following features: - the ratio (B/A) of said proximal thickness to said horizontal distance is larger than 0.75; - said recess is situated over its entire depth, possibly with the exception of the first 10% of its depth, below an imaginary line which extends through said upper edge and is inwardly sloping downward over an angle of 36 degrees; - said horizontal length, or thus the depth of the recess, is less than 2.4 mm and still better less than 2.2 mm; - said horizontal length is smaller than 0.4 times the overall thickness of the floor panel. - on the one hand, that said locking surfaces are configured such that in the coupled condition, on a location where they contact each other, they form an angle different from 90 degrees with the plane of the floor panel; - and, on the other hand, that said lip-shaped part shows at least one of the following features or a combination of any two or three of the following features, or all four of the following features: - the ratio (B/A) of said proximal thickness to said horizontal distance is larger than 0.75; - said recess is situated over its entire depth, possibly with the exception of the first 10% of its depth, below an imaginary line which extends through said upper edge and is inwardly sloping downward over an angle of 36 degrees; - said horizontal length, or thus the depth of the recess, is less than 2.4 mm and still better less than 2.2 mm; - said horizontal length is smaller than 0.4 times the overall thickness of the floor panel. - the ratio (B/A) of said proximal thickness to said horizontal distance is larger than 0.75; - said recess is situated over its entire depth, possibly with the exception of the first 10% of its depth, below an imaginary line which extends through said upper edge and is inwardly sloping downward over an angle of 36 degrees; - said horizontal length, or thus the depth of the recess, is less than 2.4 mm and still better less than 2.2 mm; - said horizontal length is smaller than 0.4 times the overall thickness of the floor panel.