Duchamps is a character in the holoprogram Julian Bashir, Secret Agent, a henchman to Dr. Hippocrates Noah and an avid baccarat player.
In 2372, Duchamps temporarily took on the physical characteristics of Worf when his transporter pattern was stored in the holodeck following the explosion of the USS Orinoco.
It was Duchamps whom Patrick Merriweather (Julian Bashir as the main character) encountered at Club Ingenue in his attempts to locate the mysterious Dr. Noah. Duchamps subsequently subdued Merriweather with a stun powder from a cigar and took him to Noah's retreat in the Himalayas. (DS9: "Our Man Bashir")
The French sounding name Duchamps is likely an homage to the James Bond spoof Casino Royale and its villain Le Chiffre. In the film a man pretending to be James Bond also plays baccarat in Paris.