Car park barrier device which comprises: - a pole, the two ends of which are pivotably linked to two bases, the pole being capable of passing via rotation from a lowered position, allowing the parking of a vehicle above the barrier, to a raised position, prohibiting parking, - a mechanism for locking the pole which comprises: -- a slide system having two tubes and slidingly mounted with respect to one another, said slide system having an end pivotably linked to the pole and another end pivotably linked to a third base, capable of passing from a deployed position in said lowered position of the pole to a retracted position in said raised position of the pole, -- a locking system capable of blocking the sliding between the two tubes and in said retracted position, - a base system rigidly connecting together the two bases of the pole and the third base of the slide system, comprising openings near the bases and for fastening members intended to anchor said base system to the floor, characterised in that said base system is a pre-cut metal sheet onto which said three bases and are rigidly connected in three distinct fastening positions, said openings for the fastening members intended to anchor said base system to the floor manifesting themselves as cutouts in said metal sheet, near said bases and, the pre-cut metal sheet has an overall shape of an arc of a circle, the two bases of the pole rigidly connected to the metal sheet at the ends of the arc and the third base of the slide system rigidly connected to the metal sheet at an intermediate position of the arc, and in that said device has two reductions in the cross-section of the metal sheet, respectively between one of the bases of the pole and the base, of the slide system on the one hand, and between said base of the slide system and the other base of said pole, on the other hand, each of the reductions in the cross-section being determined, locally in the direction of the metal sheet substantially radial to the arc, said two reductions in the cross-section of the metal sheet being configured in such a way as to form two flexible links between the three bases (4,5) and their respective openings for the fastening members. - a pole, the two ends of which are pivotably linked to two bases, the pole being capable of passing via rotation from a lowered position, allowing the parking of a vehicle above the barrier, to a raised position, prohibiting parking, - a mechanism for locking the pole which comprises: -- a slide system having two tubes and slidingly mounted with respect to one another, said slide system having an end pivotably linked to the pole and another end pivotably linked to a third base, capable of passing from a deployed position in said lowered position of the pole to a retracted position in said raised position of the pole, -- a locking system capable of blocking the sliding between the two tubes and in said retracted position, -- a slide system having two tubes and slidingly mounted with respect to one another, said slide system having an end pivotably linked to the pole and another end pivotably linked to a third base, capable of passing from a deployed position in said lowered position of the pole to a retracted position in said raised position of the pole, -- a locking system capable of blocking the sliding between the two tubes and in said retracted position, - a base system rigidly connecting together the two bases of the pole and the third base of the slide system, comprising openings near the bases and for fastening members intended to anchor said base system to the floor, characterised in that said base system is a pre-cut metal sheet onto which said three bases and are rigidly connected in three distinct fastening positions, said openings for the fastening members intended to anchor said base system to the floor manifesting themselves as cutouts in said metal sheet, near said bases and,