Distraction assembly comprising: - a plate distractor (10; 100; 200), in particular a maxillofacial plate distractor, comprising: • first and second attachment plates, • a threaded rod, • a tapped tube mounted on the threaded rod and attached to the second attachment plate, • a bush receiving the threaded rod free in rotation and fixed in translation and the tapped tube fixed in rotation and free in translation, • a permanent magnet received in a housing, extending along a main direction and magnetised along a direction transverse to the main direction, mounted in the plate distractor (10; 100; 200) such that rotation of the permanent magnet about itself, about an axis of rotation (D; D1) parallel to the main axis, causes a relative rotation of the threaded rod relative to the tapped tube, the permanent magnet being located at a distance from one of the ends of the plate distractor (10; 100; 200), measured along the direction of the axis of rotation (D; D1) of the permanent magnet, less than or equal to 15 mm, preferably the permanent magnet of the distractor being located at an end of the plate distractor, - a tool for activating the plate distractor comprising a permanent magnet, extending along a main direction (D; D1) and magnetised along a direction transverse to the main direction, characterised in that the permanent magnet of the activation tool is configured so that, when it is placed opposite the permanent magnet of the distractor, the magnetisation directions (NS; SN) of the permanent magnet of the activation tool and of the permanent magnet of the distractor are substantially parallel and the permanent magnet of the activation tool being able to drive the permanent magnet of the distractor in rotation by pivoting about itself the permanent magnet of the activation tool about an axis (D; D1) substantially colinear with the axis of the permanent magnet of the distractor. - a plate distractor (10; 100; 200), in particular a maxillofacial plate distractor, comprising: • first and second attachment plates, • a threaded rod, • a tapped tube mounted on the threaded rod and attached to the second attachment plate, • a bush receiving the threaded rod free in rotation and fixed in translation and the tapped tube fixed in rotation and free in translation, • a permanent magnet received in a housing, extending along a main direction and magnetised along a direction transverse to the main direction, mounted in the plate distractor (10; 100; 200) such that rotation of the permanent magnet about itself, about an axis of rotation (D; D1) parallel to the main axis, causes a relative rotation of the threaded rod relative to the tapped tube, the permanent magnet being located at a distance from one of the ends of the plate distractor (10; 100; 200), measured along the direction of the axis of rotation (D; D1) of the permanent magnet, less than or equal to 15 mm, preferably the permanent magnet of the distractor being located at an end of the plate distractor, • first and second attachment plates, • a threaded rod, • a tapped tube mounted on the threaded rod and attached to the second attachment plate, • a bush receiving the threaded rod free in rotation and fixed in translation and the tapped tube fixed in rotation and free in translation, • a permanent magnet received in a housing, extending along a main direction and magnetised along a direction transverse to the main direction, mounted in the plate distractor (10; 100; 200) such that rotation of the permanent magnet about itself, about an axis of rotation (D; D1) parallel to the main axis, causes a relative rotation of the threaded rod relative to the tapped tube, the permanent magnet being located at a distance from one of the ends of the plate distractor (10; 100; 200), measured along the direction of the axis of rotation (D; D1) of the permanent magnet, less than or equal to 15 mm, preferably the permanent magnet of the distractor being located at an end of the plate distractor, - a tool for activating the plate distractor comprising a permanent magnet, extending along a main direction (D; D1) and magnetised along a direction transverse to the main direction,