Joe Spinell's mother, Filomena Spagnuolo, has a cameo as the elderly owner of the Italian bakery and diner where one character eats dinner at.
The movie is based on the real life theft of massive amounts of narcotics that were confiscated from the original "French Connection" case from the early 1960's where an approximate $400 million dollars of heroin were stolen from the NYPD property clerks office located at 400 Broome Street in Manhattan, NY. The scope and depth of this scheme are still not known, but officials suspect it involved corrupt NYPD officers who allowed Vincent Papa, Virgil Allesi, Anthony Loria and other notorious mafia members access to the NYPD property/evidence storage room, where hundreds of kilograms of heroin lay seized from the now-infamous French Connection bust, and from which the men would help themselves and replace missing heroin with flour and cornstarch to avoid detection.
Richard Gere references a "Columbo" episode where a character falls in love with a hooker, calling it 'unbelievable'. Fifteen years after appearing in this film, Gere fell in love with a hooker in "Pretty Woman".