diff --git a/src/keyboard.c b/src/keyboard.c
index 6959bea7..0d8345c2 100644
--- a/src/keyboard.c
+++ b/src/keyboard.c
@@ -837,10 +837,20 @@ word Get_Key_modifiers(void)
 #if defined(WIN32)
   if (GetKeyState(VK_SHIFT) & 0x8000)
     mod |= MOD_SHIFT;
-  if (GetKeyState(VK_CONTROL) & 0x8000)
-    mod |= MOD_CTRL;
-  if (GetKeyState(VK_MENU) & 0x8000)
-    mod |= MOD_ALT;
+  // Pressing AltGr is reported by windows as the right Alt together with the Left control keys
+  if ((GetKeyState(VK_RMENU) & 0x8000) && (GetKeyState(VK_LCONTROL) & 0x8000))
+  {
+    mod |= MOD_ALT; // ALT GR
+    if (GetKeyState(VK_RCONTROL) & 0x8000)
+      mod |= MOD_CTRL;
+  }
+  else
+  {
+    if (GetKeyState(VK_CONTROL) & 0x8000)
+      mod |= MOD_CTRL;
+    if (GetKeyState(VK_MENU) & 0x8000)
+      mod |= MOD_ALT;
+  }
   if ((GetKeyState(VK_LWIN) | GetKeyState(VK_RWIN)) & 0x8000)
     mod |= MOD_META;
 #endif
diff --git a/src/win32screen.c b/src/win32screen.c
index 40c1725a..4f0b1c2e 100644
--- a/src/win32screen.c
+++ b/src/win32screen.c
@@ -159,14 +159,20 @@ static LRESULT CALLBACK Win32_WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LP
 // WM_MBUTTONDBLCLK
   case WM_SYSKEYDOWN: // Sent when ALT is pressed
   case WM_KEYDOWN:  // lParam & 0xffff => repeat count.   (lParam >> 16) & 0x1ff => scancode
+    // lParam & 0x20000000 : context : 0 for WM_KEYDOWN; 1 for WM_SYSKEYDOWN if ALT is pressed
+    // lParam & 0x40000000 : previous key state (1 down, 0 up)
+    // lParam & 0x80000000 : transition state. 0 for WM_KEYDOWN and WM_SYSKEYDOWN
+    GFX2_Log(GFX2_DEBUG, "KEYDOWN wParam=%04x lParam=%08x\n", wParam, lParam);
     switch (wParam)
     {
       // Ignore isolated shift, alt,  control and window keys
+      // and numlock
     case VK_SHIFT:
     case VK_CONTROL:
-    case VK_MENU:
+    case VK_MENU: // ALT
     case VK_LWIN:
     case VK_RWIN:
+    case VK_NUMLOCK:
       break;
     default:
       Key = wParam|Get_Key_modifiers();