From the Super Mario Wiki
Sacre is a starving artist with a French accent living on the first floor of Flipside in Super Paper Mario. He used to be very daring, but has decided to take the practical route of commercial art. Unfortunately, he has been met with very little success. Sacre lives with his daughter Ellie. His Flopside counterpart is Bleu, and together their names are a reference to the French phrase "Sacre bleu!".