A one-time henchgirl of The Riddler. She was an old family friend of the Waynes who agreed to aid The Riddler when her family suffered from poor investments.
The scheme was to break into Wayne Manor so The Riddler could investigate the 'Secret of Wayne Manor'. Quelle was to distract Bruce Wayne at a charity fundraiser that she had flown in from Paris to attend. Then she was to help break into the Manor and make sure The Riddler faced no problems in his search of the Manor.
However, the appearance of Harley Quinn and her Quinntets meant the plan faced some difficulties. Thanks to the appearance of Quinn and the later appearance of Big Barda, who was sent in to take care of the situation by Oracle, Quelle found herself seemingly abandoned by her boss.
Kennedy Two-Bear, one of Harley's Quinntets, took a shine to the French woman and even offered to let her become a Quinntet so she could get away, offering her his spare Quinntet shirt. However a Riddler henchman stole the shirt from them so he could escape and he was mistakenly shot by one of his co-henches in the process.
Quelle was captured with The Riddler and his henchmen when Barda destroyed the manor.
Kenny and Harley did discuss breaking her out of jail, however, we do not see this. It isn't clear whether she returned to Paris or stayed, but she appears not to have worked with The Riddler again.