NOVELTY - The catalytic cracking process comprises performing a cracking reaction in a bottom fluidized bed reactor (1), separating cracked hydrocarbons and catalyst coke, and fractionating the cracked hydrocarbons and a then regenerating the catalyst coke. The hydrocarbon feedstock is injected into an upstream reactor of a partially deactivated catalyst by coking so that the temperature of reaction of the effluent ranges from 470-600 degrees C. The pre-coking of the catalyst is achieved by injecting a hydrocarbon compound having a boiling temperature of 350 degrees C on a portion of regenerated catalyst.    USE - The process is useful for catalytic cracking of hydrocarbon cuts including effluents obtained from fractionation step, conversion units and/or distillation of crude oil, and cuts derived from the biomass to maximize production of diesel oils (all claimed).    ADVANTAGE - The process is capable of completely and easily catalytic cracking the hydrocarbon cuts thus maximizing the production of diesel oils with high efficiency.    DETAILED DESCRIPTION - The catalytic cracking process comprises performing a cracking reaction in a bottom fluidized bed reactor (1), separating cracked hydrocarbons and catalyst coke, and fractionating the cracked hydrocarbons and a then regenerating the catalyst coke. The hydrocarbon feedstock is injected into an upstream reactor of a partially deactivated catalyst by coking so that the temperature of reaction of the effluent in outlet of the reactor ranges from 470-600 degrees C. The pre-coking of the catalyst in the reactor is achieved by injecting a hydrocarbon compound having a boiling temperature of 350 degrees C on a portion of regenerated catalyst, where the portion is defined by an area defined by an internal device. A part of the separated catalyst coke is returned directly to the reactor in downstream of the injection of hydrocarbon feedstock at a temperature below the reaction temperature. A part of the regenerated catalyst is coked in upstream of the injection of the load by the hydrocarbon compound, and a portion (1-75%) of the stripped and recovered catalyst coke is returned in upstream and/or downstream of the injection of load into the reactor. A cut-off temperature of lower than 160 degrees C is provided on the catalyst regenerated in the reactor, during injection step. The process further comprises performing additional cracking reaction in the reactor and recycling the hydrocarbonized cut having a boiling point of lower than 145 degrees C and/or a boiling point of greater than 350 degrees C. A second upstream reactor is used for cracking of hydrocarbon cuts with a ratio of carbon and oxygen of 4-20 at 470-650 degrees C. An INDEPENDENT CLAIM is included for a device performing for catalytic cracking process to maximize production of diesel oils.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a unit comprising an upstream reactor.    Fluidized bed reactor (1)    Separator (2)    Regenerator (3)    Fractionating unit (4)    Fluid conduit (5)    Catalyst coke conduit. (6)