diff --git a/.env.example b/.env.example
index 9cbff6467e..a00366cee9 100644
--- a/.env.example
+++ b/.env.example
@@ -12,6 +12,9 @@ SITE_OWNER=mail@example.com
 # The encryption key for your sessions. Keep this very secure.
 # Change it to a string of exactly 32 chars or use something like `php artisan key:generate` to generate it.
 # If you use Docker or similar, you can set this variable from a file by using APP_KEY_FILE
+#
+# Avoid the "#" character in your APP_KEY, it may break things.
+#
 APP_KEY=SomeRandomStringOf32CharsExactly
 
 # Firefly III will launch using this language (for new users and unauthenticated visitors)