They don't allow photography in the store, but they have lovely pictures on their website, www.damboutons.com. I wish I had taken a picture of their handsome black and white Spitz, though, sitting in that doorway and vetting the customers.
The mouths are from Salvador Dali (they had a number of buttons celebrating the artists that hung out in Montmartre). The big red ones are actually from a trim shop that we passed walking through the Arts and Metiers district.
And then there was Le Petit Pan, a store that features charming things for tiny children in fabrics from Japan, but one of their storefronts in the Marais was fabric lengths, buttons and trim.