diff --git a/lidar_pipeline/dtm.py b/lidar_pipeline/dtm.py
index be7e613..b57e3f4 100644
--- a/lidar_pipeline/dtm.py
+++ b/lidar_pipeline/dtm.py
@@ -312,6 +312,7 @@ def _read_with_pdal(laz_file):
     import tempfile
     import os
 
+    tmp_path = None
     try:
         # Convert COPC to LAS via PDAL, then read with laspy
         with tempfile.NamedTemporaryFile(suffix='.las', delete=False) as tmp:
@@ -331,18 +332,10 @@ def _read_with_pdal(laz_file):
 
         if result.returncode != 0:
             logger.warning(f"  PDAL conversion échouée: {result.stderr[:200]}")
-            try:
-                os.unlink(tmp_path)
-            except Exception:
-                pass
             return None
 
         import laspy
         las = laspy.read(tmp_path)
-        try:
-            os.unlink(tmp_path)
-        except Exception:
-            pass
         if len(las.points) == 0:
             logger.warning(f"  PDAL: conversion réussie mais 0 points")
             return None
@@ -351,6 +344,14 @@ def _read_with_pdal(laz_file):
     except Exception as e:
         logger.warning(f"  PDAL fallback échoué: {e}")
         return None
+    finally:
+        # Toujours supprimer le LAS temporaire, même en cas d'exception
+        # (timeout subprocess, laspy.read échoué…) : sinon fuite de ~Go.
+        if tmp_path:
+            try:
+                os.unlink(tmp_path)
+            except Exception:
+                pass
 
 
 def detect_ground_method(laz_file):