Résumé : Robotic microassembly is a promising way to fabricate micrometric components based three dimensions (3D) compound products where the materials or the technologies are incompatible: structures, devices, Micro Electro Mechanical Systems (MEMS), Micro Opto Electro Mechanical Systems (MOEMS),... To date, solutions proposed in the literature are based on 2D visual control because of the lack of accurate and robust 3D measures from the work scene. In this paper the relevance of the real-time 3D visual tracking and control is demonstrated. The 3D poses of the MEMS is supplied by a model-based tracking algorithm in real-time. It is accurate and robust enough to enable a precise regulation toward zero of a 3D error using a visual servoing approach. The assembly of 400 mm 400 mm 100 mm parts by their 100 mm 100 mm 100 mm notches with a mechanical play of 3 mm is achieved with a rate of 41 seconds per assembly. The control accuracy reaches 0.3 mm in position and 0.2 in orientation.