Two words. ALMOND CROISSANT.
It's huge [insert 'that's what she said' joke here] and has a good amount of almond filling. So I would try to split it with someone as a dessert (rather than try to devour the whole thing as breakfast like I did) because it can be a little too heavy for the morning hours.
Le Cartet is a cute cafe with plenty of seating. They sell European snacks/gifts in the front (such as jam, candy, coffee, etc.) You can also get your coffee to go. And it ain't just 'coffee' anymore. So many different varieties to choose from!
Service was quick (and they're nice enough to give you their wifi password if you're not from town).
Do yourself a favor and go get that croissant, NOW!