CoRoT (Convection, Rotation and planetary Transits) is a satellite mission led by CNES. CoRot has been successfully launched on December 27th of 2006. One of its goals is to discover new exo-planets using the transit method. It observes stars and sample their emission light every 512 seconds leading to observing runs of 12000 light curves over a 6 months period. For each run, 1000 of these light curves can be over-sampled up to 32 second allowing a transit detection. In order to select the targets to be over-sampled, the ground segment team at LAM set up an infrastructure to get and analyse preliminary N1 data within a week delay. The selected target are ordered in a list transmitted to the "Centre de Mission Corot" (CMC). We present the infrastructure of the over-sampling mode, the over-sampling software used for detection in raw light-curves and the mechanisms of list ordering and selection. This paper describes as well the feed back over the past one and a half year of operation.