On the building we can see a big 'M'. On a building more at left (not visible) is a big 'A' (see picture 116837). Together they mean "Atelier Central de Meknès".
On the first building of the "Atelier Central de Meknès" we can see a decorative big 'A'; the second building (not visible on this picture) has a big 'M' on it (see photo 116901).