The Laboratory of study of microstructures, mechanics and material sciences (in French: Laboratoire d'étude des microstructures et de mécanique des matériaux), also known as the LEM3, is a French laboratory of research located in Metz. It is under the authority of Arts et Métiers ParisTech, University of Lorraine and ENIM. It is part of the Carnot Institute ARTS and currently employs more than 150 persons. It was created in 2011 from the merge of 2 CNRS laboratories, the LPMM and the LETAM. The LEM3 plays an important role in the competitiveness organization "Materialia" and in the new research institute M2P.