You're what the French call Les incompetents.
5 seconds sound clip from the Home Alone (1990) movie soundboard.
You can hear this line at 00:04:25 in the Blu-ray version of the movie.
Quote context
[...]
- Excuse me, puke-breath. I'm a lot smaller than you. I don't know how to pack a suitcase.
- I hope you didn't just pack crap, Jeff.
- Do you know what I should pack?
- Buzz told you, cheek-face: toilet paper and water.
- Listen, Kev, what are you so worried about? You know mom's gonna pack your stuff anyway.
- You're what the French call Les incompetents.
- What?
- P.S. You have to sleep on the hide-a-bed with Fuller.
- If he has something to drink, he's gonna wet the bed.
- This house is so full of people, it makes me sick! When I grow up and get married, I'm livin' alone!
[...]