A lighting system comprising: - a supporting and power-supply guide, and - a lighting apparatus; the lighting apparatus comprising: - a connection body, and - a lighting body with at least one light source; wherein said lighting body is mechanically and electrically connected to said connection body, wherein said connection body is adapted for being mechanically and electrically connected to said guide that extends in a longitudinal direction, wherein said connection body is shaped like an elongated box and is adapted for being inserted into and extracted from said guide at least in a direction perpendicular to the length thereof and to said longitudinal direction keeping said connection body and said guide parallel to each other both in the insertion operation and in the extraction operation, and wherein said connection body comprises two mechanical contacts (16A, 16B, 16C) and two electrical contacts (15A, 15B), and elastic means (17A, 17B 18B, 18C) acting on said two mechanical contacts (16A, 16B, 16C) and on said two electrical contacts (15A, 15B) so as to allow them to be moved back-and-forth due to the insertion into and the extraction from said guide; wherein said two electrical contacts are arranged to cooperate respectively with two electrical conductors of said guide; wherein said two mechanical contacts are arranged to cooperate respectively with two internal grooves without electrical conductors on the side of said guide; wherein said two mechanical contacts (16A, 16B, 16C) and said two electrical contacts (15A, 15B) have inclined surfaces so that when said connection body moves towards or away from said guide and goes in contact with components of said guide, said contacts (15A, 15B, 16A, 16B, 16C) tend to move in a direction perpendicular to the towards/away direction and retract by application of a force to said connection body that is contrasted by said elastic means (17A, 17B 18B, 18C) that tend to return said contacts (15A, 15B, 16A, 16B, 16C) to a protruding position. - a supporting and power-supply guide, and - a lighting apparatus; - a connection body, and - a lighting body with at least one light source; wherein said lighting body is mechanically and electrically connected to said connection body, wherein said connection body is adapted for being mechanically and electrically connected to said guide that extends in a longitudinal direction, wherein said connection body is shaped like an elongated box and is adapted for being inserted into and extracted from said guide at least in a direction perpendicular to the length thereof and to said longitudinal direction keeping said connection body and said guide parallel to each other both in the insertion operation and in the extraction operation, and wherein said connection body comprises two mechanical contacts (16A, 16B, 16C) and two electrical contacts (15A, 15B), and elastic means (17A, 17B 18B, 18C) acting on said two mechanical contacts (16A, 16B, 16C) and on said two electrical contacts (15A, 15B) so as to allow them to be moved back-and-forth due to the insertion into and the extraction from said guide; wherein said two electrical contacts are arranged to cooperate respectively with two electrical conductors of said guide; wherein said two mechanical contacts are arranged to cooperate respectively with two internal grooves without electrical conductors on the side of said guide; wherein said two mechanical contacts (16A, 16B, 16C) and said two electrical contacts (15A, 15B) have inclined surfaces so that when said connection body moves towards or away from said guide and goes in contact with components of said guide, said contacts (15A, 15B, 16A, 16B, 16C) tend to move in a direction perpendicular to the towards/away direction and retract by application of a force to said connection body that is contrasted by said elastic means (17A, 17B 18B, 18C) that tend to return said contacts (15A, 15B, 16A, 16B, 16C) to a protruding position.