Method for synthetizing a fluorescent tracer for targeting tumors, said fluorescent tracer comprising: - at least a first fluorophore comprising a carbon-based chain comprising at least a sequence of at least three covalent carbon-carbon double bonds, so as to enable delocalization of the electrons of the double bonds when the fluorophore is excited by light radiation so as to fluoresce with an emission peak of between 770 nm and 870 nm, - an assembly for targeting integrin comprising at least two identical targeting molecules, comprising cyclic pentapeptides, the peptide sequence of the pentapeptides targeting an integrin comprise the amino acid residues [-arginine - glycine - aspartic acid-], and - a cyclic decapeptide: ▪ configured so as to define a mean plane (Pm) defining a first upper face (F s) and a second lower face (F i), ▪ comprising at least a first lysine (K i) amino acid residue on the second lower face (F i), ▪ the targeting molecules being fixed to the first upper face (F s) of the mean plane (Pm), ▪ the fluorophore being fixed to the second lower face (F i) of the mean plane (Pm) via a spacer arm connecting a carbon of the sequence of the at least three covalent carbon-carbon double bonds and the lysine (K i) amino acid residue of the decapeptide; said method comprising at least the following steps: - a step of preparing a modified fluorophore, wherein a spacer arm is coupled to at least a first fluorophore comprising a carbon-based chain comprising at least a sequence of at least three covalent carbon-carbon double bonds, so as to enable delocalization of the electrons of the double bonds when the fluorophore is excited by light radiation, so as to fluoresce in a range of wavelengths of between 700 nm and 1000 nm; - a step in which said cyclic decapeptide is coupled to said modified fluorophore; - a step of coupling a targeting assembly, comprising at least two identical targeting molecules, and said cyclic decapeptide, which is coupled to said modified fluorophore. - at least a first fluorophore comprising a carbon-based chain comprising at least a sequence of at least three covalent carbon-carbon double bonds, so as to enable delocalization of the electrons of the double bonds when the fluorophore is excited by light radiation so as to fluoresce with an emission peak of between 770 nm and 870 nm, - an assembly for targeting integrin comprising at least two identical targeting molecules, comprising cyclic pentapeptides, the peptide sequence of the pentapeptides targeting an integrin comprise the amino acid residues [-arginine - glycine - aspartic acid-], and - a cyclic decapeptide: ▪ configured so as to define a mean plane (Pm) defining a first upper face (F s) and a second lower face (F i), ▪ comprising at least a first lysine (K i) amino acid residue on the second lower face (F i), ▪ the targeting molecules being fixed to the first upper face (F s) of the mean plane (Pm), ▪ the fluorophore being fixed to the second lower face (F i) of the mean plane (Pm) via a spacer arm connecting a carbon of the sequence of the at least three covalent carbon-carbon double bonds and the lysine (K i) amino acid residue of the decapeptide; ▪ configured so as to define a mean plane (Pm) defining a first upper face (F s) and a second lower face (F i), ▪ comprising at least a first lysine (K i) amino acid residue on the second lower face (F i), ▪ the targeting molecules being fixed to the first upper face (F s) of the mean plane (Pm), ▪ the fluorophore being fixed to the second lower face (F i) of the mean plane (Pm) via a spacer arm connecting a carbon of the sequence of the at least three covalent carbon-carbon double bonds and the lysine (K i) amino acid residue of the decapeptide; - a step of preparing a modified fluorophore, wherein a spacer arm is coupled to at least a first fluorophore comprising a carbon-based chain comprising at least a sequence of at least three covalent carbon-carbon double bonds, so as to enable delocalization of the electrons of the double bonds when the fluorophore is excited by light radiation, so as to fluoresce in a range of wavelengths of between 700 nm and 1000 nm; - a step in which said cyclic decapeptide is coupled to said modified fluorophore; - a step of coupling a targeting assembly, comprising at least two identical targeting molecules, and said cyclic decapeptide, which is coupled to said modified fluorophore.