Locking system for a sectional door gate comprising: - a carriage, - an intermediate part connected to the carriage so as to be moved with it, characterised in that said intermediate part includes a projecting part forming a first bolt and a housing having a stop surface (52, 54), and in that the locking system further includes: - a strike complementarily shaped to the first bolt, having retaining means suitable for the first bolt and intended to be mounted in a fixed upright, - a second bolt intended to be mounted on the sectional door gate, of a shape suitable for the housing of the intermediate part, mobile in this housing between a closing position, wherein it bears on the stop surface (52, 54) preventing the exit thereof outside of said housing and a release position, wherein said second bolt avoids the stop surface (52, 54) and can exit from said housing, thus releasing the gate from the intermediate part, - a flexible element to make the second bolt pass from the closing position thereof to the release position thereof, and - a system for releasing the first bolt with respect to the strike actuated by a control part carried by the intermediate part, the release system being able to engage with the retaining means so as to release the first bolt and the control part acting on the release system when the second bolt goes back into the housing thereof in the intermediate part. - a carriage, - an intermediate part connected to the carriage so as to be moved with it, characterised in that said intermediate part includes a projecting part forming a first bolt and a housing having a stop surface (52, 54), and in that the locking system further includes: - a strike complementarily shaped to the first bolt, having retaining means suitable for the first bolt and intended to be mounted in a fixed upright, - a second bolt intended to be mounted on the sectional door gate, of a shape suitable for the housing of the intermediate part, mobile in this housing between a closing position, wherein it bears on the stop surface (52, 54) preventing the exit thereof outside of said housing and a release position, wherein said second bolt avoids the stop surface (52, 54) and can exit from said housing, thus releasing the gate from the intermediate part, - a flexible element to make the second bolt pass from the closing position thereof to the release position thereof, and - a system for releasing the first bolt with respect to the strike actuated by a control part carried by the intermediate part, the release system being able to engage with the retaining means so as to release the first bolt and the control part acting on the release system when the second bolt goes back into the housing thereof in the intermediate part. - a strike complementarily shaped to the first bolt, having retaining means suitable for the first bolt and intended to be mounted in a fixed upright, - a second bolt intended to be mounted on the sectional door gate, of a shape suitable for the housing of the intermediate part, mobile in this housing between a closing position, wherein it bears on the stop surface (52, 54) preventing the exit thereof outside of said housing and a release position, wherein said second bolt avoids the stop surface (52, 54) and can exit from said housing, thus releasing the gate from the intermediate part, - a flexible element to make the second bolt pass from the closing position thereof to the release position thereof, and - a system for releasing the first bolt with respect to the strike actuated by a control part carried by the intermediate part, the release system being able to engage with the retaining means so as to release the first bolt and the control part acting on the release system when the second bolt goes back into the housing thereof in the intermediate part.