Status of the OPERA experiment at the CNGS beam

The OPERA experiment, located in the Gran Sasso underground laboratory, is designed to directly detect the appearance of $ν$ in a pure $ν$ beam (CNGS) produced at CERN, travelling over a distance of 730 km. Taus produced in $ν$ charged current interactions are identified by reconstructing their decay topology with the nuclear emulsion technique. After a short introduction on the physics motivations and on the principle of the tau topological detection, the OPERA hybrid detector will be described. The analysis flow will be explained in details and first physics results presented.