An installation for planishing running metal of strip or plate products includes: a frame in which are disposed a lower planishing cassette and an upper planishing cassette, a lower drive device for driving planishing rollers of the lower cassette in rotation, an upper drive device for driving planishing rollers of the upper cassette in rotation. A displacement device displaces a secured assembly including the lower cassette and lower drive. The displacement device is activated for removal of the lower cassette from the frame toward one side or for insertion of the lower cassette from the one side into the frame. The secured assembly includes a replacement tool coupled to the lower cassette on a second operator side opposite the first motor side in relation to the product running axis. A method associated with the planishing installation is also described.