All municipal sewage treatments using classic treatment chain create an amount of organic sludge. The stabilization/neutralization of them is essential before any conditioning or reuse. For agronomical recycling or energy-giving optimization, the sludge needs to correspond to some standards. That's why, it exist several treatment of stabilization, packaging and water extraction of sludge. This study deals with sludge chemical conditioning by flocculation process. In the first hand, the flocculation process allows to break up colloidal aversion between particles in sludge. This process is possible by charge neutralization thanks to synthetic or natural organic flocculation which is often cationic since the ionic force of sludge particle usually is negative and the flocculants can be used with lowest dose than common coagulant like aluminum sulfate or ferric chloride. Thanks to laboratory experiments by analysis of several doses of synthesis cationic flocculants, it has been possible to get performance on total suspended solids (TSS), by spectrophotometry measurement and consistency of sludge cake. Graphical analyses allow making comparison between some organic cationic flocculants and select the best one for this type of sludge and the kind of treatment used. The aim is to improve quality of sludge, quantity of filtrated volume, and quality of water.