A tracking dyeing method for colouring or dyeing a natural fibre to be marked or identified, comprising the following steps: f) preparing a natural fibre in a dye tank; g) adding a siloxane agent in said tank; subsequently h) dispersing a liquid colouring solution comprising a pigment in said tank; i) heating said dye tank comprising said natural fibre, said siloxane agent and said colouring solution at a temperature comprised between 50°C and 70 °C, preferably at 60 °C; j) keeping said temperature constant for a time comprised between 1 and 3 hours; wherein said pigment is a piezochromic pigment, comprising: - an inorganic matrix having a lamellar conformation, - an organic filler configured to be intercalated or absorbed between the lamellae of said inorganic matrix, said pigment having a first configuration, at a first pressure value (P1), wherein said inorganic matrix lamellae are spaced apart and at least one organic filling layer is positioned between two of said lamellae, and a second configuration, at a second pressure value (P2), said second pressure (P2) being higher than said first pressure (P1), wherein said inorganic matrix lamellae are close together allowing a molecular aggregation of said organic filler, said molecular aggregation generating a change in pigment coloration such that, in a configuration of use of the pigment applied to the support surface, when compression is applied to a portion of the treated support surface, the pigment changes from said first to said second configuration, resulting in a change in coloration of the portion of the treated surface that has been subjected to compression with respect to the remaining treated surface not subjected to compression allowing a marking or identification of authenticity of the treated support surface. f) preparing a natural fibre in a dye tank; g) adding a siloxane agent in said tank; subsequently h) dispersing a liquid colouring solution comprising a pigment in said tank; i) heating said dye tank comprising said natural fibre, said siloxane agent and said colouring solution at a temperature comprised between 50°C and 70 °C, preferably at 60 °C; j) keeping said temperature constant for a time comprised between 1 and 3 hours; wherein said pigment is a piezochromic pigment, comprising: - an inorganic matrix having a lamellar conformation, - an organic filler configured to be intercalated or absorbed between the lamellae of said inorganic matrix, - an inorganic matrix having a lamellar conformation, - an organic filler configured to be intercalated or absorbed between the lamellae of said inorganic matrix, said pigment having a first configuration, at a first pressure value (P1), wherein said inorganic matrix lamellae are spaced apart and at least one organic filling layer is positioned between two of said lamellae, and a second configuration, at a second pressure value (P2), said second pressure (P2) being higher than said first pressure (P1), wherein said inorganic matrix lamellae are close together allowing a molecular aggregation of said organic filler, said molecular aggregation generating a change in pigment coloration such that, in a configuration of use of the pigment applied to the support surface, when compression is applied to a portion of the treated support surface, the pigment changes from said first to said second configuration, resulting in a change in coloration of the portion of the treated surface that has been subjected to compression with respect to the remaining treated surface not subjected to compression allowing a marking or identification of authenticity of the treated support surface. <EOS>