A device for levelling coating parts; applicable in the coplanar arrangement of said coating parts during the installation thereof; the device comprising: an actuation tool; a first part provided with a base and a rod; a second part provided with a through-opening suitable for mounting on the rod of the first part and can be moved towards the base thereof and with a surface for supporting the actuation tool; and the actuation tool being adapted for moving the second part along the rod of the first part towards an operative position in which the first part and second part exert a pressure on two opposite faces of at least two adjacent coating parts, the actuation tool comprising a first arm and a second arm articulated on an intermediate shaft, having respective ends (31a, 32a) for acting on the first part and the second part, and respective handles (31 b and 32b); characterized in that the rod of the first part has at least one hole or recess for the engagement of the actuation tool and in that the actuation tool further comprises a positioning mechanism for positioning the arms (31, 32) of the tool in positions with different degrees of opening and for regulating the rotational relative movement of said arms (31, 32) in each of the said positions, the positioning mechanism comprising: a separator provided with a longitudinal slotted hole in which a pin of the first arm of the tool is mounted and can be rotated and moved along the same; said separator having on a first side an alignment of recesses that define, in a coupling position with a secured tooth of the second arm, relative positions of the arms (31, 32) of the tool with different degrees of opening; and a spring that acts with the opposite ends on the first arm and the separator, said spring tending to maintain the separator in a coupling position in anyone of the recesses with the secured tooth of the second arm and to maintain the tool in an inoperative position, determined by the contact of the pin with said end of the slotted hole farthest from the second arm of the tool. a first part provided with a base and a rod; a second part provided with a through-opening suitable for mounting on the rod of the first part and can be moved towards the base thereof and with a surface for supporting the actuation tool; and the actuation tool being adapted for moving the second part along the rod of the first part towards an operative position in which the first part and second part exert a pressure on two opposite faces of at least two adjacent coating parts, the actuation tool comprising a first arm and a second arm articulated on an intermediate shaft, having respective ends (31a, 32a) for acting on the first part and the second part, and respective handles (31 b and 32b); characterized in that the rod of the first part has at least one hole or recess for the engagement of the actuation tool and in that the actuation tool further comprises a positioning mechanism for positioning the arms (31, 32) of the tool in positions with different degrees of opening and for regulating the rotational relative movement of said arms (31, 32) in each of the said positions, the positioning mechanism comprising: a separator provided with a longitudinal slotted hole in which a pin of the first arm of the tool is mounted and can be rotated and moved along the same; said separator having on a first side an alignment of recesses that define, in a coupling position with a secured tooth of the second arm, relative positions of the arms (31, 32) of the tool with different degrees of opening; and a spring that acts with the opposite ends on the first arm and the separator, said spring tending to maintain the separator in a coupling position in anyone of the recesses with the secured tooth of the second arm and to maintain the tool in an inoperative position, determined by the contact of the pin with said end of the slotted hole farthest from the second arm of the tool. a separator provided with a longitudinal slotted hole in which a pin of the first arm of the tool is mounted and can be rotated and moved along the same; said separator having on a first side an alignment of recesses that define, in a coupling position with a secured tooth of the second arm, relative positions of the arms (31, 32) of the tool with different degrees of opening; and a spring that acts with the opposite ends on the first arm and the separator, said spring tending to maintain the separator in a coupling position in anyone of the recesses with the secured tooth of the second arm and to maintain the tool in an inoperative position, determined by the contact of the pin with said end of the slotted hole farthest from the second arm of the tool.