Although Jean is not in the final film, you can see her in this posed still from the nightclub scene (far left in the top photo). She and her mother were hired to be extras in this scene. According to his press agent, Carlyle Robinson, Chaplin was evidently quite taken with the blonde bombshell:
While City Lights was in the making, Charlie became interested in a young woman, an extra. The peculiar color of her hair attracted him. She was provocatively alluring.
At the same table at which this extra girl was seated was an older woman. I learned they were mother and daughter. He instructed me to have the older woman promoted! She should play the bit of the indignant matron who sits upon the burning cigar in that sequence. It was only when he discovered that the woman had her hair cut in a boyish bob that he changed his mind.
At the time I made a note that the name of the mother and daughter was Pope*–a Mrs. Pope and Jean Pope. Later I discovered that the girl had blossomed forth–in Hell’s Angels – as Jean Harlow! The mother was now Mrs. Marino Bello. (Carlyle Robinson, “The Private Life Of Charlie Chaplin,” Liberty, Winter 1972)
*Instead of Pope, Robinson may have meant Poe, Jean’s mother’s middle name.