Jack Smallhorn cites Charlotte Blong as marrying Paris Singer (the Singer Sewing Machines heir) and living a high life of yachts and money. However she could not have been his wife as there is no record of her marrying Paris Singer in the available information on his life, and secondly she was born around 1830, and probably no later than 1835, and was therefore at least 30 years older than him as Paris Singer was born 1867. Paris Singer's father had around 25 children by at least 5 different women, however Charlotte Blong does not feature on this list either (nor are their any Charlottes or variations on it).
On re-reading Jack Smallhorn's information I see that he refers to Charlotte as a "cousin" which could actually be anything. However the fact remains that Paris Singer never married a Charlotte Blanc