A computer-implemented method for localizing a 3D modeled object in a 3D scene, the 3D modeled object and the 3D scene each including respective 3D points, each 3D point being associated to a respective normal vector, the method comprising a positioning of the 3D modeled object in the 3D scene, the positioning being performed following an algorithm that rewards, for each of first couples made of two 3D points of the 3D modeled object and their respective associated normal vectors, a match with a respective second couple made of two 3D points of the 3D scene and their respective associated normal vectors, the first couple being positioned substantially on the second couple, the match between the first couple and the second couple amounting to a substantial equality between the value of a descriptor for the first couple and the value of the descriptor for the second couple, characterized in that the substantial equality between the value of the descriptor for the first couple and the value of the descriptor for the second couple is a substantial equality between a first integer number corresponding to the value of the descriptor for the first couple and a second integer number corresponding to the value of the descriptor for the second couple, the first integer number and the second integer number being computed via a quantization mapping applied respectively to the value of the descriptor for the first couple and to the value of the descriptor for the second couple, wherein the quantization mapping is of the type σ: P M ∪ P S → H → N defined by composition σ = Q ∘ F, where for all (( p 1, n 1),( p 2, n 2)) ∈ P M ∪ P S: σ p 1 n 1 p 2 n 2 = Q F p 1 n 1 p 2 n 2 and where: ▪ B = x y z ∈ R 3, x 2 + y 2 + z 2 = 1 is the unit sphere, ▪ K = R 3 × B is the set of couples made of a 3D point and a normal vector, ▪ M is the 3D modeled object, including a finite subset of K, with M = { m i, i = 1,···,| M |} with m i ∈ R 3 × B for all i, ▪ S is the 3D scene, including a finite subset of K, with S = { s i, i = 1,···,| S |} with s i ∈ R 3 × B for all i, ▪ P M is the set of all couples of elements of M, with P M = {(( p 1, n 1), ( p 2, n 2)),( p 1, n 1) ∈ M, ( p 2, n 2) ∈ M} = M × M, ▪ P S. is the set of all couples of elements of S, with P S = {(( p 1, n 1), ( p 2, n 2)),( p 1, n 1) ∈ S,( p 2, n 2) ∈ S} = S × S, and ▪ H = F ( P M ∪ P S) is the finite set of all 4-tuples of real numbers ( r 1, r 2, r 3, r 4) = F ( p 1, n 1, p 2, n 2) when (( p 1, n 1), ( p 2, n 2)) ∈ P M ∪ P S, ▪ Q: H → N is the quantization mapping, with Q ( r 1, r 2, r 3, r 4) = q 1 δ 2 δ 3 δ 4 + q 2 δ 3 δ 4 + q 3 δ 4 + q 4, ▪ q i = r i ε i − r i min ε i, with q i integer numbers defined for i = 1,···,4 given an arbitrary 4-tuple ( r 1, r 2, r 3, r 4) = F ( p 1, n 1, p 2, n 2) ∈ H, ▪ δ i for i = 1,...,4 are integer numbers defined as δ i = r i max ε i − r i min ε i, with [ r] denoting the greatest integer number less than or equal to a given real number r, ▪ ε i, i = 1,···,4 are four real numbers that represent the resolutions of the quantization, and ▪ r i min and r i max with i = 1,···,4 are eight real numbers such that, for i = 1,···,4 and all ( r 1, r 2, r 3, r 4) ∈ H, r i min ≤ r i ≤ r i max. ▪ B = x y z ∈ R 3, x 2 + y 2 + z 2 = 1 is the unit sphere, ▪ K = R 3 × B is the set of couples made of a 3D point and a normal vector, ▪ M is the 3D modeled object, including a finite subset of K, with M = { m i, i = 1,···,| M |} with m i ∈ R 3 × B for all i, ▪ S is the 3D scene, including a finite subset of K, with S = { s i, i = 1,···,| S |} with s i ∈ R 3 × B for all i, ▪ P M is the set of all couples of elements of M, with P M = {(( p 1, n 1), ( p 2, n 2)),( p 1, n 1) ∈ M, ( p 2, n 2) ∈ M} = M × M, ▪ P S. is the set of all couples of elements of S, with P S = {(( p 1, n 1), ( p 2, n 2)),( p 1, n 1) ∈ S,( p 2, n 2) ∈ S} = S × S, and ▪ H = F ( P M ∪ P S) is the finite set of all 4-tuples of real numbers ( r 1, r 2, r 3, r 4) = F ( p 1, n 1, p 2, n 2) when (( p 1, n 1), ( p 2, n 2)) ∈ P M ∪ P S, ▪ Q: H → N is the quantization mapping, with Q ( r 1, r 2, r 3, r 4) = q 1 δ 2 δ 3 δ 4 + q 2 δ 3 δ 4 + q 3 δ 4 + q 4, ▪ q i = r i ε i − r i min ε i, with q i integer numbers defined for i = 1,···,4 given an arbitrary 4-tuple ( r 1, r 2, r 3, r 4) = F ( p 1, n 1, p 2, n 2) ∈ H, ▪ δ i for i = 1,...,4 are integer numbers defined as δ i = r i max ε i − r i min ε i, with [ r] denoting the greatest integer number less than or equal to a given real number r, ▪ ε i, i = 1,···,4 are four real numbers that represent the resolutions of the quantization, and ▪ r i min and r i max with i = 1,···,4 are eight real numbers such that, for i = 1,···,4 and all ( r 1, r 2, r 3, r 4) ∈ H,