diff --git a/zsh/.config/zsh/config.d/10_aliases.zsh b/zsh/.config/zsh/config.d/10_aliases.zsh
index a769305..65d9d93 100644
--- a/zsh/.config/zsh/config.d/10_aliases.zsh
+++ b/zsh/.config/zsh/config.d/10_aliases.zsh
@@ -48,6 +48,16 @@ if [ "$TERM_PROGRAM" = "vscode" ]; then
     alias code='code -r'
 fi
 
+# Ban `flatpak --user` for consistency
+function flatpak {
+    if [[ "$*" == *" --user "* ]] || [[ "$*" == *" -u "* ]]; then
+        echo '`flatpak --user` is illegal, all apps should be in `--system`.' >&2
+        echo '(Use `command flatpak --user` if you really need to for some reason.)' >&2
+        return 1
+    fi
+    command flatpak $@
+}
+
 # A function which toggles the status of a systemd service
 function systemctl_toggle {
 	if systemctl is-active --quiet $1; then