A baby crib , comprising: - a frame comprising: - a lower structure configured to support a mattress , - an upper structure spaced apart from the lower structure , - uprights that connect and fix the lower structure and the upper structure together, - a guide having a top end portion proximate to the upper structure and a bottom end portion proximate to the lower structure , - a movable bar having a slider that is slidable along the guide , the movable bar and the upper structure together surrounding an upper opening when the slider is at the top end of the guide , - a textile enclosure having a bottom substantially level with the lower structure , side walls that connect the bottom to the upper structure , and a movable wall , connected to the movable bar , - a constraint member configured to be secured to a structural member of a bed, wherein - the constraint member is constrained to the guide and is movable relative to the guide between a position close to the guide and a position spaced apart from the guide , characterized in that it comprises a return system configured to return the slider toward the top end portion of the guide , the constraint member being connected to the return system so as to be returned by the return system toward the close position, and to prevent the return system from returning the slider when the constraint member is retained in the spaced-apart position. - a frame comprising: - a lower structure configured to support a mattress , - an upper structure spaced apart from the lower structure , - uprights that connect and fix the lower structure and the upper structure together, - a guide having a top end portion proximate to the upper structure and a bottom end portion proximate to the lower structure , - a movable bar having a slider that is slidable along the guide , the movable bar and the upper structure together surrounding an upper opening when the slider is at the top end of the guide , - a lower structure configured to support a mattress , - an upper structure spaced apart from the lower structure , - uprights that connect and fix the lower structure and the upper structure together, - a guide having a top end portion proximate to the upper structure and a bottom end portion proximate to the lower structure , - a movable bar having a slider that is slidable along the guide , the movable bar and the upper structure together surrounding an upper opening when the slider is at the top end of the guide , - a textile enclosure having a bottom substantially level with the lower structure , side walls that connect the bottom to the upper structure , and a movable wall , connected to the movable bar , - a constraint member configured to be secured to a structural member of a bed, wherein - the constraint member is constrained to the guide and is movable relative to the guide between a position close to the guide and a position spaced apart from the guide , characterized in that it comprises a return system configured to return the slider toward the top end portion of the guide , the constraint member being connected to the return system so as to be returned by the return system toward the close position, and to prevent the return system from returning the slider when the constraint member is retained in the spaced-apart position. <EOS>