diff --git a/cpp/kiss_icp/core/Preprocessing.hpp b/cpp/kiss_icp/core/Preprocessing.hpp
index 0042837a..69cc9935 100644
--- a/cpp/kiss_icp/core/Preprocessing.hpp
+++ b/cpp/kiss_icp/core/Preprocessing.hpp
@@ -28,9 +28,6 @@
 #include <vector>
 
 namespace kiss_icp {
-/// Voxelize point cloud keeping the original coordinates
-std::vector<Eigen::Vector3d> VoxelDownsample(const std::vector<Eigen::Vector3d> &frame,
-                                             const double voxel_size);
 
 /// Crop the frame with max/min ranges
 std::vector<Eigen::Vector3d> Preprocess(const std::vector<Eigen::Vector3d> &frame,
@@ -42,4 +39,7 @@ std::vector<Eigen::Vector3d> Preprocess(const std::vector<Eigen::Vector3d> &fram
 /// Originally introduced the calibration factor)
 std::vector<Eigen::Vector3d> CorrectKITTIScan(const std::vector<Eigen::Vector3d> &frame);
 
+/// Voxelize point cloud keeping the original coordinates
+std::vector<Eigen::Vector3d> VoxelDownsample(const std::vector<Eigen::Vector3d> &frame,
+                                             const double voxel_size);
 }  // namespace kiss_icp