A fuel injector comprising: a nozzle with a body extending along a main axis, said body having a peripheral wall defining an internal bore in which a needle is axially moveable, said nozzle having an end provided with one or more injection orifices to form a spray extremity; wherein said needle extends along a needle axis and has an overall shape with symmetry of revolution about said needle axis, said needle comprising a shaft portion which is tapered at said first end and defines a male seating face that cooperates with a female tapered seating face in said bore, upstream of said injection orifice(s), such that in a closed state, said male seating face sealingly engages said female seating face to prevent fuel injection through said injection orifice(s), and such that in an open state, said needle is lifted from said female seating to allow fuel injection; wherein said needle includes a protruding annular collar that divides the internal volume of said bore in an upstream chamber, wherein in use, pressurized fuel flows in, and a downstream chamber provided with said injection orifice(s); a control chamber associated with a control valve arrangement, said control valve arrangement allowing to selectively vary, in use, a fuel pressure in said control chamber and thereby control an opening or closing move of said needle, said control valve arrangement configured to be actuated by an actuator; wherein said fuel injector further includes a detection circuit in which said needle forms a switch; wherein said female tapered seating face is generally conical, said male tapered seating face including a conical surface having an angle (β) greater than 75°; said collar includes substantially symmetrically configured passage means (36.1) for allowing fuel to flow from said upstream chamber to said downstream chamber; and said control valve arrangement is configured as a three-way valve; wherein said control valve arrangement includes: a fuel escape path connecting the control chamber to a low pressure side of the injector and that can be selectively opened and closed; and a fuel feed path connecting the control chamber to a high pressure side of the injector and that can be selectively opened and closed; and wherein said fuel escape path includes a spill orifice and said fuel feed path includes an inlet orifice, said spill orifice defining a larger flow cross-section than said inlet orifice. a nozzle with a body extending along a main axis, said body having a peripheral wall defining an internal bore in which a needle is axially moveable, said nozzle having an end provided with one or more injection orifices to form a spray extremity; wherein said needle extends along a needle axis and has an overall shape with symmetry of revolution about said needle axis, said needle comprising a shaft portion which is tapered at said first end and defines a male seating face that cooperates with a female tapered seating face in said bore, upstream of said injection orifice(s), such that in a closed state, said male seating face sealingly engages said female seating face to prevent fuel injection through said injection orifice(s), and such that in an open state, said needle is lifted from said female seating to allow fuel injection; wherein said needle includes a protruding annular collar that divides the internal volume of said bore in an upstream chamber, wherein in use, pressurized fuel flows in, and a downstream chamber provided with said injection orifice(s); a control chamber associated with a control valve arrangement, said control valve arrangement allowing to selectively vary, in use, a fuel pressure in said control chamber and thereby control an opening or closing move of said needle, said control valve arrangement configured to be actuated by an actuator; wherein said fuel injector further includes a detection circuit in which said needle forms a switch; wherein said female tapered seating face is generally conical, said male tapered seating face including a conical surface having an angle (β) greater than 75°; said collar includes substantially symmetrically configured passage means (36.1) for allowing fuel to flow from said upstream chamber to said downstream chamber; and said control valve arrangement is configured as a three-way valve; wherein said control valve arrangement includes: a fuel escape path connecting the control chamber to a low pressure side of the injector and that can be selectively opened and closed; and a fuel feed path connecting the control chamber to a high pressure side of the injector and that can be selectively opened and closed; and a fuel escape path connecting the control chamber to a low pressure side of the injector and that can be selectively opened and closed; and a fuel feed path connecting the control chamber to a high pressure side of the injector and that can be selectively opened and closed; and wherein said fuel escape path includes a spill orifice and said fuel feed path includes an inlet orifice, said spill orifice defining a larger flow cross-section than said inlet orifice.