diff --git a/locales/en.json b/locales/en.json
index e4f785002..50ef2ddf1 100644
--- a/locales/en.json
+++ b/locales/en.json
@@ -20,7 +20,7 @@
     "app_location_already_used": "An app is already installed in this location",
     "app_location_install_failed": "Unable to install the app in this location",
     "app_location_unavailable": "This url is not available or conflicts with an already installed app",
-    "app_manifest_invalid": "Invalid app manifest",
+    "app_manifest_invalid": "Invalid app manifest: {error}",
     "app_no_upgrade": "No app to upgrade",
     "app_not_correctly_installed": "{app:s} seems to be incorrectly installed",
     "app_not_installed": "{app:s} is not installed",
diff --git a/src/yunohost/app.py b/src/yunohost/app.py
index aa76cfc7f..bb81efeeb 100644
--- a/src/yunohost/app.py
+++ b/src/yunohost/app.py
@@ -1424,6 +1424,9 @@ def _extract_app_from_file(path, remove=False):
             manifest['lastUpdate'] = int(time.time())
     except IOError:
         raise MoulinetteError(errno.EIO, m18n.n('app_install_files_invalid'))
+    except ValueError as e:
+        raise MoulinetteError(errno.EINVAL,
+                              m18n.n('app_manifest_invalid', error=e.strerror))
 
     logger.info(m18n.n('done'))
 
@@ -1517,9 +1520,9 @@ def _fetch_app_from_git(app):
             except subprocess.CalledProcessError:
                 raise MoulinetteError(errno.EIO,
                                       m18n.n('app_sources_fetch_failed'))
-            except IOError:
+            except ValueError as e:
                 raise MoulinetteError(errno.EIO,
-                                      m18n.n('app_manifest_invalid'))
+                                      m18n.n('app_manifest_invalid', error=e.strerror))
             else:
                 logger.info(m18n.n('done'))
 
@@ -1574,9 +1577,9 @@ def _fetch_app_from_git(app):
             except subprocess.CalledProcessError:
                 raise MoulinetteError(errno.EIO,
                                       m18n.n('app_sources_fetch_failed'))
-            except IOError:
+            except ValueError as e:
                 raise MoulinetteError(errno.EIO,
-                                      m18n.n('app_manifest_invalid'))
+                                      m18n.n('app_manifest_invalid', error=e.strerror))
             else:
                 logger.info(m18n.n('done'))