A fire extinguisher including: - a sealed tank extending along an axis which, in a given orientation of use of the extinguisher, is vertical relative to a horizontal plane or forms a few degrees of inclination angle relative to the vertical, the sealed tank comprising a liquid to be sprayed, for example water, the tank being configured to comprise an expansion chamber formed by a part of the tank not filled with the liquid to be sprayed, - a sealed expellant bottle, comprising a pressurized propellant gas, for use as a propellant for the liquid to be sprayed, the expellant bottle being housed inside the tank and having, for the propellant gas, an outlet fluidly connected to the inside of the tank, - a mixing tube fluidly connected to the outlet of the expellant bottle and having an outlet provided to be immersed in the liquid to be sprayed, - wherein the extinguisher comprises a fluorine-free additive for the liquid to be sprayed, for example an extinguishing agent, and means for receiving the fluorine-free additive, these receiving means being housed inside the tank and capable of isolating the additive from the liquid to be sprayed, characterized in that: - the mixing tube has at least one orifice lateral to the axis configured to release at least part of the contents of the expellant bottle in the expansion chamber of the tank, - the expellant bottle forms the means for receiving the additive, the expellant bottle containing the pressurized propellant gas and the fluorine-free additive without partitioning between them, such that the propellant gas drives the additive towards the liquid to be sprayed, through the outlet of the expellant bottle for the propellant gas. - a sealed tank extending along an axis which, in a given orientation of use of the extinguisher, is vertical relative to a horizontal plane or forms a few degrees of inclination angle relative to the vertical, the sealed tank comprising a liquid to be sprayed, for example water, the tank being configured to comprise an expansion chamber formed by a part of the tank not filled with the liquid to be sprayed, - a sealed expellant bottle, comprising a pressurized propellant gas, for use as a propellant for the liquid to be sprayed, the expellant bottle being housed inside the tank and having, for the propellant gas, an outlet fluidly connected to the inside of the tank, - a mixing tube fluidly connected to the outlet of the expellant bottle and having an outlet provided to be immersed in the liquid to be sprayed, - wherein the extinguisher comprises a fluorine-free additive for the liquid to be sprayed, for example an extinguishing agent, and means for receiving the fluorine-free additive, these receiving means being housed inside the tank and capable of isolating the additive from the liquid to be sprayed, - the mixing tube has at least one orifice lateral to the axis configured to release at least part of the contents of the expellant bottle in the expansion chamber of the tank, - the expellant bottle forms the means for receiving the additive, the expellant bottle containing the pressurized propellant gas and the fluorine-free additive without partitioning between them, such that the propellant gas drives the additive towards the liquid to be sprayed, through the outlet of the expellant bottle for the propellant gas.