diff --git a/sat/core/constants.py b/sat/core/constants.py
index e998b4d4..379a45a2 100644
--- a/sat/core/constants.py
+++ b/sat/core/constants.py
@@ -218,7 +218,10 @@ class Const(object):
                 ]
             )
 
-            if os.getenv('FLATPAK_ID'):
+            # on recent versions of Flatpak, FLATPAK_ID is set at run time
+            # it seems that this is not the case on older versions,
+            # but FLATPAK_SANDBOX_DIR seems set then
+            if os.getenv('FLATPAK_ID') or os.getenv('FLATPAK_SANDBOX_DIR'):
                 # for Flatpak, the conf can't be set in /etc or $HOME, so we have
                 # to add /app
                 CONFIG_PATHS.append('/app/')