NOVELTY - Fuel cell system includes: at least one fuel cell adapted to generate electrical energy from a fuel gas and an oxidizer gas; a fuel feed duct (11) provided for supplying fuel cell with fuel gas, where fuel feed duct includes upstream part (11A) and downstream part; a Venturi effect ejector (113) including a high pressure inlet, low pressure inlet and an outlet; an off-gas recirculation duct (11R) extending between the fuel cell and the low pressure ejector inlet; and a control circuit and a valve arranged in the upstream part of fuel feed duct and arranged to be controlled by control circuit.    USE - The fuel cell system is useful in an electric energy production system, which is useful in an automobile vehicle.    ADVANTAGE - The fuel cell system: allows limiting the mass flow rate of the fuel gas passing through the ejector, while at the same time, maintaining a flow of fuel gas intense enough to produce the Venturi effect; utilizes the valve and the ejector that form an integral part, hence it can be implemented without making the system more complex; avoids the occurrence of flooding; and is capable of consuming entire hydrogen and the oxygen.    DETAILED DESCRIPTION - Fuel cell system includes: at least one fuel cell adapted to generate electrical energy from a fuel gas and an oxidizer gas; a fuel feed duct (11) provided for supplying the fuel cell with fuel gas, where the fuel feed duct includes an upstream part (11A) and a downstream part; a Venturi effect ejector (113) including a high pressure inlet, a low pressure inlet and an outlet, where the upstream part of the fuel feed duct is connected to the high pressure inlet of the ejector, and the downstream part extends between the ejector outlet and the fuel cell; an off-gas recirculation duct (11R) extending between the fuel cell and the low pressure ejector inlet, so that in the presence of a stream of fuel gas coming from the upstream part of the fuel feed duct and passing through the ejector, the ejector draws up off-gas from the recirculation duct and ejects it into the downstream part mixed with the stream of fuel gas coming from the upstream part; and a control circuit and a valve arranged in the upstream part of the fuel feed duct and arranged to be controlled by the control circuit, where the valve is adapted to be placed in an open state, in which it lets the stream of fuel gas from the upstream part pass through the ejector, or in a closed state, in which no stream of gas from the upstream part can flow through the ejector. The control circuit is arranged to place the valve alternately in the open state and then the closed state, so that the stream of fuel gas passing through the ejector is intermittent, being frequency and/or pulse width modulated by the control circuit.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic representation of part of the fuel cell system.    Fuel feed duct (11)    Upstream part of the fuel feed duct (11A)    Off-gas recirculation duct (11R)    Oxidizer feed duct (12)    Ejector (113)