A fairlead for guiding an anchor chain, intended to equip a system for anchoring a floating platform to the ground, wherein said fairlead comprises: (i) a bending structure, for guiding a direction change of said associated anchor chain, and (ii) a locking structure which comprises a grip jaw consisted of two articulated jaws and associated with means for their operation in rotation in opposite directions, between: - an active position, for locking in translation said anchor chain in an upstream to downstream direction, and - an inactive position, wherein said jaws are spaced apart so as to allow the translation of the chain within said fairlead, and said operating means comprise: (a) an inert mass, referred to as "counterweight", which is movably coupled to said jaws and which is operable in a height direction between a low position and a high position corresponding to said active position and said inactive position of said jaws, respectively, so as to operate and to tend to hold said jaws in said active position, and (b) an actuator mean (26, 35), driven by control means, for operating said jaws from said active position to said inactive position and for operating said counterweight from said low position to said high position, characterized in that said jaws are articulated around rotation axes parallel to each other. (i) a bending structure, for guiding a direction change of said associated anchor chain, and (ii) a locking structure which comprises a grip jaw consisted of two articulated jaws and associated with means for their operation in rotation in opposite directions, between: - an active position, for locking in translation said anchor chain in an upstream to downstream direction, and - an inactive position, wherein said jaws are spaced apart so as to allow the translation of the chain within said fairlead, and said operating means comprise: (a) an inert mass, referred to as "counterweight", which is movably coupled to said jaws and which is operable in a height direction between a low position and a high position corresponding to said active position and said inactive position of said jaws, respectively, so as to operate and to tend to hold said jaws in said active position, and (b) an actuator mean (26, 35), driven by control means, for operating said jaws from said active position to said inactive position and for operating said counterweight from said low position to said high position, characterized in that said jaws are articulated around rotation axes parallel to each other. - an active position, for locking in translation said anchor chain in an upstream to downstream direction, and - an inactive position, wherein said jaws are spaced apart so as to allow the translation of the chain within said fairlead, and said operating means comprise: (a) an inert mass, referred to as "counterweight", which is movably coupled to said jaws and which is operable in a height direction between a low position and a high position corresponding to said active position and said inactive position of said jaws, respectively, so as to operate and to tend to hold said jaws in said active position, and (b) an actuator mean (26, 35), driven by control means, for operating said jaws from said active position to said inactive position and for operating said counterweight from said low position to said high position, characterized in that said jaws are articulated around rotation axes parallel to each other. (a) an inert mass, referred to as "counterweight", which is movably coupled to said jaws and which is operable in a height direction between a low position and a high position corresponding to said active position and said inactive position of said jaws, respectively, so as to operate and to tend to hold said jaws in said active position, and (b) an actuator mean (26, 35), driven by control means, for operating said jaws from said active position to said inactive position and for operating said counterweight from said low position to said high position,