The Dogue De Bordeaux is a hard-working breed that will tirelessly perform for a loving handler.  Despite their 'sour' appearance, the Dogue tends to be a very sensitive breed that will shut down in the face of harsh treatment or even tone of voice.  Example: At an agility competition, Jade ran into the wrong end of the tunnel.  Exasperated, I said "NO, Jade!". Jade promptly came out of the tunnel, looked at me with disdain and left me in the ring by myself (with the judge).  Jade retreated to the gate to await her 'chariot' (the car). It was as if "You're so smart, YOU run the course by yourself!". What a great lesson for me!  The DDB is NOT for the novice dog owner.  Positive reinforcement as a training method is an absolute MUST.  The Monks of New Skete training techniques are recommended by us to anyone considering a DDB of their own.